19. ISC Physics

8/7/2019 19. ISC Physics

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PHYSICS (861)Aims:

1. To enable candidates to acquire knowledge andto develop an understanding of the terms, facts,concepts, definitions, fundamental laws,

principles and processes in the field of physics.

2. To develop the ability to apply the knowledgeand understanding of physics to unfamiliar situations.

3. To develop a scientific attitude through the studyof physical sciences.

4. To develop skills in -

(a) the practical aspects of handling apparatus,recording observations and

(b) drawing diagrams, graphs, etc.5. To develop an appreciation of the contribution

of physics towards scientific and technologicaldevelopments and towards human happiness.

6. To develop an interest in the world of physicalsciences.

CLASS XI

T here will be two papers in the subject.

Paper I : Theory - 3 hour ... 70 marks Paper II : Practical - 3 hours ... 20 marks

Project Work 7 marks Practical File 3 marks

PAPER I -THEORY 70 Marks

Paper I shall be of 3 hours duration and be divided into two parts.

Part I (20 marks): This part will consist of compulsory short answer questions, testing knowledge, application and skills relating toelementary/fundamental aspects of the entire syllabus.

Part II (50 marks): This part will be divided intothree Sections A, B and C. There shall besix questions in Section A (each carrying 7 marks) and candidates are required to answer four questions from this Section. There shall bethree questions inSection B (each carrying 6 marks) and candidates arerequired to answer two questions from this Section.There shall bethree questions in Section C (eachcarrying 5 marks) and candidates are required toanswer two questions from this Section. Therefore,candidates are expected to answer eight questions in Part II. ote: Unless otherwise specified, only S. I. Units areto be used while teaching and learning, as well as for answering questions.

SECTIO A

1. Role of Physics(i) Scope of Physics.

Applications of Physics to everyday life. relation with other science disciplin Physics learning and phenomena of nadevelopment of spirit of inquiry, observameasurement, analysis of data, interpretaof data and scientific temper; appreciationthe beauty of scheme of nature.

(ii) Role of Physics in technology.

Physics as the foundation of all techadvances - examples. Quantitative approof physics as the beginning of technolTechnology as the extension of app physics. Growth of technology made poby advances in physics. Fundamental lawnature are from physics. Technology is on the basic laws of physics.

(iii) Impact on society.

Effect of discoveries of laws of nature o philosophy and culture of people. Effe growth of physics on our understandinnatural phenomenon like lighting athunder, weather changes, rain, etc. Effe study of quantum mechanics, dual natumatter, nuclear physics and astronomy onmacroscopic and microscopic picture ofuniverse.


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2. Units

(i) SI units. Fundamental and derived units(correct symbols for units includingconventions for symbols).

Importance of measurement in scientific studies; physics is a science of measurement.Unit as a reference standard of measurement;essential properties. Systems of unit; CGS, FPS, MKSA, and SI; the seven base units of SI selected by the General Conference of Weights and Measures in 1971 and their definitions; list of fundamental physical quantities; their units and symbols, strictly as per rule; subunits and multiple units using prefixes for powers of 10 (from atto for 10-18 to tera for 1012 ); other common units suchas fermi, angstrom (now outdated), light year,astronomical unit and parsec. A new unit of mass used in atomic physics is unified atomicmass unit with symbol u (not amu); rules for writing the names of units and their symbolsin SI (upper case/lower case, no period after symbols, etc.) Derived units (with correct symbols); special names wherever applicable; expression interms of base units (eg: = kgm/s2 ).

(ii) Accuracy and errors in measurement, leastcount of measuring instruments (and theimplications for errors in experimentalmeasurements and calculations).

Accuracy of measurement, errors inmeasurement: instrumental errors, systematicerrors, random errors and gross errors. Least count of an instrument and its implication for errors in measurements; absolute error,relative error and percentage error;combination of error in (a) sum and difference, (b) product and quotient and (c) power of a measured quantity.

(iii) Significant figures and order of accuracy withreference to measuring instruments. Powers of 10 and order of magnitude.

What are significant figures? Their significance; rules for counting the number of significant figures; rules for (a) addition and subtraction, (b) multiplication/division;rounding off the uncertain digits; order of magnitude as statement of magnitudes in powers of 10; examples from magnitudes of common physical quantities - size, mass, time,etc.

3. Dimensions(i) Dimensional formula of physical quantities

and physical constants like g, h, etc. (fromMechanics only).

Dimensions of physical quadimensional formula; express derived unterms of base units ( = kg.ms-2 ); use symbol

[...] for dimension of or base unit ex: dimensional formula of force in termbase units is written as [F]=[MLT 2 ]. Expressions in terms of SI base units mobtained for all physical quantities as when new physical quantities are introduc

(ii) Dimensional equation and its use to check correctness of a formula, to find the relation

between physical quantities, to find thedimension of a physical quantity or constant;limitations of dimensional analysis.Use of dimensional analysis to (i) check

dimensional correctness of a formuequation, (ii) to obtain the exact dependof a physical quantity on other mechanvariables, and (iii) to obtain the dimensi formula of any derived physical quaincluding constants; limitations dimensional analysis.

4. Vectors, Scalar Quantities and ElementaryCalculus

(i) Vectors in one dimension, two dimensions andthree dimensions, equality of vectors and nullvector.

Vectors explained using displacement a prototype - along a straight (one dimension), on a plane surfa(two dimension) and in open space confined to a line or plane (three dimens symbol and representation; a scalar quanits representation and unit, equality vectors. Unit vectors denoted i , j ,k orthogonal unit vectors along x, y

z axes respectively. Examples of dimensional vector 1V

r

=ai or bj or ck where a, b, c are scalar quantities numbers; 2 V

r

= ai + b j is a two dimensionavector, 3V

r

= a i + b j + ck is a threedimensional vector. Define and discussneed of a null vector. Concept of co-plvectors.


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(ii) Vector operations (addition, subtraction andmultiplication of vectors including use of unit

vectors i , j ,k ); parallelogram and trianglelaw of vector addition.

Addition: use displacement as an example;obtain triangle law of addition; graphical and

analytical treatment; Discuss commutative and associative properties of vector addition (Proof not required). Parallelogram Law; sum and difference; derive expression for magnitudeand directions from a parallelogram; special cases; subtraction as special case of additionwith direction reversed; use of Triangle Law for subtraction also; if ar + b

r

= cr ; cr - ar = br

; In a parallelogram, if one diagonal is the sum,the other diagonal is the difference; additionand subtraction with vectors expressed interms of unit vectorsi , j ,k ; multiplication of a vector by real numbers.

(iii) Resolution and components of like vectors in a plane (including rectangular components),scalar (dot) and vector (cross) products.

Use triangle law of addition to express avector in terms of its components. If ar +b

r

=cr is an addition fact,cr = ar + br

is aresolution;ar and b

r

are components of cr . Rectangular components, relation betweencomponents, resultant and angle in between.

Dot (or scalar) product of vectors or scalar product ar .br

=abcos ; example W = F r

.S r

Special case of = 0, 90 and 1800. Vector (or cross) product ar xb

r

=[absin ]n ; example:torque r = r r x F

r

; Special cases using unit vectorsi , j ,k for ar .b

r

and ar xbr

. [Elementary Calculus: differentiation and integration as required for physics topics inClasses XI and XII. o direct question will beasked from this subunit in the examination].

Differentiation as rate of change; examples from physics speed, acceleration, etc. Formulae for differentiation of simple functions: xn , sinx, cosx, e x and ln x. Simpleideas about integration mainly. xn.dx. Bothdefinite and indefinite integral should beexplained.

5. Dynamics

(i) Cases of uniform velocity, equations of uniformly accelerated motion and applicationsincluding motion under gravity (close tosurface of the earth) and motion along asmooth inclined plane.

Review of rest and motion; distancedisplacement, speed and velocity, ave speed and average velocity, uniform veloinstantaneous speed and instantaneovelocity, acceleration, instantaneoacceleration, s-t, v-t and a-t graphs uniform acceleration and discussion of uinformation obtained from the grapkinematic equations of motion for objecuniformly accelerated rectilinear moderived using calculus or otherwise, motian object under gravity, (one dimensiomotion). Acceleration of an object moviand down a smooth inclined plane.

(ii) Relative velocity, projectile motion.Start from simple examples on relavelocity of one dimensional motion andtwo dimensional motion; considisplacement first; relative displacem(use Triangle Law); - AB A BS S S =

r r r

thendifferentiating we get AB A Bv v v=

r r r

; projectile motion; Equation of trajecobtain equations for max. height, velorange, time of flight, etc; relation betwhorizontal range and vertical ran[projectile motion on an inclined plane included]. Examples and problems projectile motion.

(iii) Newton's laws of motion and simpleapplications. Elementary ideas on inertial anduniformly accelerated frames of reference.

[Already done in Classes IX and X, so hereit can be treated at higher maths level usingvectors and calculus].

ewton's first law: Statement explanation; inertia, mass, force definitilaw of inertia; mathematically, if F=0, a=0.

ewton's second law: pr =mvr ; F r

dpdt

r

;

F r

=k dpdt

r

. Define unit of force so th


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k=1; F r

= dpdt

r

; a vector equation. For

classical physics with v not large and massm remaining constant, obtain F

r

=mar . For v c, m is not constant. Thenm = 2 2

o

c v - 1

m . ote that F= ma is the

special case for classical mechanics. It is avector equation.ar || F

r

. Also, this can beresolved into three scalar equations F x=ma x etc. Application to numerical problems;introduce tension force, normal reaction force. If a = 0 (body in equilibrium), F= 0. Impulse F t = p; unit; problems. ewton's third law. Simple ideas withexamples of inertial and uniformlyaccelerated frames of reference. Simple

applications of ewtons laws: tension,normal reaction; law of conservation of momentum. Systematic solution of problemsin mechanics; isolate a part of a system,identify all forces acting on it; draw a freebody diagram representing the part as a point and representing all forces by line segments, solve for resultant force which is equal tomar . Simple problems on Connected bodies(not involving two pulleys).

(iv) Concurrent forces (reference should be madeto force diagrams and to the point of application of forces), work done by constantand variable force (Spring force).

Force diagrams; resultant or net force fromlaw of Triangle of Forces, parallelogram lawor resolution of forces. Apply net force F

r

= mar . Again for equilibrium a=0and F=0. Conditions of equilibrium of a rigid body under three coplanar forces. Discuss ladder problem. Work done W= F

r

.S r

=FScos . If F isvariable dW= F

r

.dSr

and W= dw= F

r

. dS r

,

for F r

dS r

F r

.dS r

=FdS therefore, W= FdS is the area under the F-S graph or if F can beexpressed in terms of S, FdS can beevaluated. Example, work done in stretching a

spring 212

W Fdx kxdx kx= = = . This is

also the potential energy stored in stretched spring U= kx2 .

(v) Energy, conservation of energy, power,conservation of linear momentum, impulse,elastic and inelastic collisions in one and twodimensions.

E=W. Units same as that of work W; laconservation of energy; oscillating sprU+K = E = K max= U max(for U = 0 and K = 0respectively); different forms of en E = mc2; no derivation. Power P=W/t; uni

. P F v=r

r ; conservation of linear moment(done under ewton's 3rd law); impulse Ft or F t. unit .s and joule- done under 2nd law.Collision in one dimension; derivationvelocity equation for general case of m1 m2 and u1 u2=0; Special cases for m1=m2=m;m1>>m2 or m1


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(theorem); assumptions - incompressibleliquid, streamline (steady) flow, non-viscousand irrotational liquid - ideal liquid;derivation of equation; applications of Bernoullis theorem as given in the syllabus. Discuss in brief: Pressure in a fluid, Pascalslaw.

(ii) Stream line and turbulent flow, Reynold'snumber (derivation not required).

Streamline and turbulent flow - examples;trajectory of fluid particles; streamlines donot intersect (like electric and magnetic linesof force); tubes of flow; number of streamlines per unit area velocity of flow (fromequation of continuity v1a1 = v2a2 ); critical velocity; Reynolds number - no derivation,but check dimensional correctness.(Poisseulles formula excluded).

(iii) Viscous drag; Newton's formula for viscosity,co-efficient of viscosity and its units. Flow of fluids (liquids and gases), laminar flow, internal friction between layers of fluid,between fluid and the solid with which the fluid is in relative motion; examples; viscousdrag is a force of friction; mobile and viscousliquids.Velocity gradient dv/dx (space rate of changeof velocity); viscous drag F = A dv/dx;coefficient of viscosity = F/A(dv/dx)depends on the nature of the liquid and itstemperature; units: s/m2 and dyn.s/cm2= poise. 1 poise=0.1 s/m2; value of for a few selected fluids.

(iv) Stoke's law, terminal velocity of a spherefalling through a fluid or a hollow rigid sphererising to the surface of a fluid.

Motion of a sphere falling through a fluid,hollow rigid sphere rising to the surface of aliquid, parachute, terminal velocity; forcesacting; buoyancy (Archimedes principle);viscous drag, a force proportional to velocity;Stokes law; -t graph.

8. Circular Motion

(i) Centripetal acceleration and force, motionround a banked track, point mass at the end of a light inextensible string moving in(i) horizontal circle (ii) vertical circle and aconical pendulum.

Definition of centripetal acceleration; deexpression for this acceleration usTriangle Law to find v r . Magnitude anddirection of a same as that of v r ;Centripetal acceleration; the cause of acceleration is a force - also callcentripetal force; the name only indicatedirection, it is not a new type of force, it cbe mechanical tension as in motion of a pmass at the end of a light inextensible stmoving in a circle, or electric as on electron in Bohr model of atom, or magas on any charged particle moving inmagnetic field [may not introduce centrif force]; conical pendulum, formulacentripetal force and tension in the strmotion in a vertical circle; banking of rand railway track.

(ii) Centre of mass, moment of inertia:rectangular rod; disc; ring; sphere. Definition of centre of mass (cm) for a particle system moving in one dimem1 x1+m2 x2=Mxcm; differentiating, get thequation for vcmand acm; general equation for particles- many particles system; [need go into more details]; concept of a rigid bkinetic energy of a rigid body rotating ab fixed axis in terms of that of the particlthe body; hence define moment of inertiaradius of gyration; unit and dimensiodepend on mass and axis of rotation; irotational inertia; applications: deriexpression for the moment of inertia, I (athe symmetry axis) of (i) a particle rotatia circle (e.g. electron in Bohr model H atom); (ii) a ring; also I of a thin rorectangular strip, a rectangular block, a soand hollow sphere, a ring, a disc and a hocylinder - only formulae (no derivation).

(iii) Parallel axis theorem and perpendicular axistheorem; radius of gyration.

Statement of the theorems with illustra[derivation not required]. Simple applicatto the cases derived under 8(ii), with chof axis.

(iv) Torque and angular momentum, relation between torque and moment of inertia and between angular momentum and moment of inertia; conservation of angular momentumand applications.


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Definition of torque (vector); r = r r x F r

and angular momentuml

r

= r r x pr for a particle; differentiate to obtain d l

r

/dt= r ; similar to ewtons second law of motion(linear); angular velocity =v/r and angular acceleration =a/r , hence = I and l = I ; (only scalar equation); Law of conservation of angular momentum; simpleapplications.

(v) Two-dimensional rigid body motion, e.g. point mass on string wound on a cylinder (horizontal axis rotation), cylinder rollingdown inclined plane without sliding.

In addition to the above, also cover: motion of a ring and a ball rolling down an inclined plane; expression for linear and rotational acceleration (a, ) and tension (T) in the

string in the first case (point mass on a string)and kinetic energy (K) for the second case(rolling down an inclined plane).

9. Gravitation

(i) Newton's law of universal gravitation;gravitational constant (G); gravitationalacceleration on surface of the earth (g).

Statement; unit and dimensional formula of universal gravitational constant, G[Cavendish experiment not required]; weight of a body W= mg from F=ma.

(ii) Relation between G and g; variation of gravitational acceleration above and below thesurface of the earth.

From the ewtons Law of Gravitation and Second Law of Motion g = Gm/R2 applied toearth. Variation of g above and below the surface of the earth; graph; mention variationof g with latitude and rotation, (without derivation).

(iii) Gravitational field, its range, potential, potential energy and intensity.

Define gravitational field, intensity of gravitational field and potential at a point inearths gravitational field. V p = W p /mo. Derive the expression (by integration) for the gravitational potential differenceV = V B-V A = G.M(1/r A-1/r B ); here V p = V(r) = -GM/r;negative sign for attractive force field; define

gravitational potential energy of a mass the earth's field; obtain expression gravitational potential energy U(r) = W p=m.V(r) = -G M m/r; show that for a nolarge change in distanceU = mgh. Relationbetween intensity and acceleration due gravity. Compare its range with thoselectric, magnetic and nuclear fields.

(iv) Escape velocity (with special reference to theearth and the moon); orbital velocity and

period of a satellite in circular orbit(particularly around the earth).

Define and obtain expression for the esvelocity from earth using enerconsideration; ve depends on mass of thearth; from moon ve is less as mass of moon less; consequence - no atmosphere on moon; satellites (both natural (moon) artificial satellite) in uniform circular mo

around the earth; orbital velocity and t period; note the centripetal acceleratiocaused (or centripetal force is providedthe force of gravity exerted by the earth o satellite; the acceleration of the satellite iacceleration due to gravity [g= g(R/R+2; F G= mg].

(v) Geostationary satellites - uses of communication satellites.

Conditions for satellite to be geostationUses.

(vi) Kepler's law of planetary motion. Explain the three laws using diagrams. Pof second and third law (circular orbits onderive only T 2 R3 from 3rd law for circulaorbits.

SECTIO B

10. Properties of Matter - Temperature

(i) Properties of matter: Solids: elasticity insolids, Hookes law, Young modulus and itsdetermination, bulk modulus and modulus of rigidity, work done in stretching a wire.

Liquids: surface tension (molecular theory),drops and bubbles, angle of contact, work done in stretching a surface and surfaceenergy, capillary rise, measurement of surfacetension by capillary rise methods. Gases:kinetic theory of gases: postulates, molecular

speeds and derivation of p= 2c , equation


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of state of an ideal gas pV = nRT (numerical problems not included from gas laws). For solids and liquids; the scope as givenabove is clear. For gases; derive p=1/3 2c from the assumptions and applying ewtonslaws of motion. The average thermal velocity

(rms value) crms= 3p/

; calculate for air,hydrogen and their comparison with common

speeds of transportation. Effect of temperature and pressure on rms speed of gasmolecules. [ ote that pV=nRT the ideal gasequation cannot be derived from kinetictheory of ideal gas. Hence, neither can other gas laws; pV=nRT is an experimental result.Comparing this with p = 2c , from kinetictheory of gas a kinetic interpretation of temperature can be obtained as explained inthe next subunit].

(ii) Temperature: kinetic interpretation of temperature (relation between c2 and T);absolute temperature. Law of equipartition of energy (statement only).

From kinetic theory for an ideal gas (obeying all the assumptions especially nointermolecular attraction and negligibly small size of molecules, we get p = (1/3) 2c or pV = (1/3)M 2c . ( o further, as temperatureis not a concept of kinetic theory). Fromexperimentally obtained gas laws we have theideal gas equation (obeyed by some gases at low pressure and high temperature) pV = RT for one mole. Combining these two results(assuming they can be combined), RT=(1/3)M 2c =(2/3).M 2c =(2/3)K; Hence,kinetic energy of 1 mole of an ideal gas K=(3/2)RT. Average K for 1 molecule = K/ = (3/2) RT/ = (3/2) kT where k is Boltzmanns constant. So, temperature T canbe interpreted as a measure of the averagekinetic energy of the molecules of a gas.

Degrees of freedom, statement of the law of equipartition of energy. Scales of temperature - only Celsius, Fahrenheit and Kelvin scales.

11. Internal Energy

(i) First law of thermodynamics.

Review the concept of heat (Q) as the ethat is transferred (due to temperatudifference only) and not stored; the enthat is stored in a body or system as poteand kinetic energy is called internal ene(U). Internal energy is a state property (elementary ideas) whereas, heat is not; law is a statement of conservation of enwhen, in general, heat (Q) is transferred body (system), internal energy (U) of system changes and some work W is dothe system; then Q=U+W; also W= pdV for working substance an ideal gas; explainmeaning of symbols (with examples) andconvention carefully (as used in physics: when to a system,U>0 when U increases otemperature rises, and W>0 when wordone by the system). Special cases for (adiabatic),U=0 (isothermal) and W=(isochoric).

(ii) Isothermal and adiabatic changes in a perfectgas described in terms of curves for PV = constant and PV = constant; joule andcalorie relation (derivation for PV = constant not included).

Self-explanatory. ote that 1 cal = 4 186 J exactly and J (so-called mechaniequivalent of heat) should not be usedequations. In equations, it is understoodeach term as well as the LHS and RHS athe same units; it could be all joules orcalories.

(iii) Work done in isothermal and adiabaticexpansion; principal molar heat capacities; C p and C v; relation between C p and C v (C p - C v = R). C p and C v for monatomic anddiatomic gasses.

Self-explanatory. Derive the relations.Work done as area bounded by PV graph.

(iv) Second law of thermodynamics, Carnot'scycle. Some practical applications.

Only one statement each in terms of Kelimpossible steam engine and Clausimpossible refrigerator. Brief explanatiolaw. Carnots cycle - describe realisat from source and sink of infinite thecapacity, thermal insulation, etc. Explain


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graph (isothermal and adiabatic of proper slope); obtain expression for efficiency =1-T 2 /T 1.

(vi) Thermal conductivity; co-efficient of thermalconductivity, Use of good and poor conductors, Searles experiment. [Lees Discmethod is not required]. comparison of thermal and electrical conductivity.Convection with examples.

Define coefficient of thermal conductivity from the equation for heat flow Q = KA d /dt;temperature gradient; Comparison of thermal and electrical conductivities (briefly). Examples of convection.

(vii) Thermal radiation: nature and properties of thermal radiation, qualitative effects of natureof surface on energy absorbed or emitted byit; black body and black body radiation,

Stefan's law (using Stefan's law to determinethe surface temperature of the sun or a star bytreating it as a black body); Newton's law of cooling, Wien's displacement law, distributionof energy in the spectrum of black bodyradiation (only qualitative and graphicaltreatment).

Black body is now called ideal or cavityradiator and black body radiation is cavityradiation; Stefans law is now known asStefan Boltzmann law as Boltzmann derived it theoretically. There is multiplicity of technical terms related to thermal radiation - radiant intensity I (T) for total radiant power (energyradiated/second) per unit area of the surface,in W/m2 , I (T) = T 4; dimensions and SI unit of . For practical radiators I = . T 4 where (dimension less) is called emmissivity of the surface material; =1 for ideal radiators.The Spectral radiancy R( ). I (T)=

0 R

( ) d . Graph of R( ) vs for different temperatures. Area under the graphis I (T). The corresponding to maximumvalue of R is called max; decreases withincrease in temperature. max 1/T; m.T=2898 m.K - Weinsdisplacement law; application to determinetemperature of stars, numerical problems. From known temperature, we get I (T)= T 4.The luminosity (L) of a star is the total power

radiated in all directions L=4 r 2.I from the solar radiant power received per unit arethe surface of the earth (at noon), the distof the sun and the radius of the sun itselfcan calculate the radiant intensity I of theand hence the temperature T of its surusing Stefans law. umerical proble

Cover ewtons law of cooling brienumerical problems to be cover[Deductions from Stefans law not necess

SECTIO C

12. Oscillations

(i) Simple harmonic motion.(ii) Expressions for displacement, velocity and

acceleration.

(iii) Characteristics of simple harmonic motion.

(iv) Relation between linear simple harmonicmotion and uniform circular motion.(v) Kinetic and potential energy at a point in

simple harmonic motion.

(vi) Derivation of time period of simple harmonicmotion of a simple pendulum, mass on aspring (horizontal and vertical oscillations).

Periodic motion, period T and frequen f=1/T; uniform circular motion and projection on a diameter defines Sdisplacement, amplitude, phase and ep

velocity, acceleration, time periocharacteristics of SHM; differential equaof SHM, d 2 y/dt 2+ 2 y=0 from the nature o force acting F=-k y; solution y=A sin ( t+ 0 )where 2 = k/m; expression for time perioand frequency f. Examples, simple penda mass m attached to a spring of sprconstant k. Total energy E = U+K (pote+kinetic) is conserved. Draw graphs of and E Vs y.

(vii) Free, forced and damped oscillations(qualitative treatment only). Resonance.

Examples of damped oscillations oscillations are damped); graph of amplivs time for undamped and damposcillations; damping force (-bv) in addto restoring force (-ky); forced oscillatiexamples; action of an external perio force, in addition to restoring force. T


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period is changed to that of the external applied force, amplitude (A) varies with frequency of the applied force and it ismaximum when the f of the external applied force is equal to the natural frequency of thevibrating body. This is resonance; maximumenergy transfer from one body to the other;

bell graph of amplitude vs frequency of theapplied force. Examples from mechanics,electricity and electronics (radio).

13. Waves

(i) Transverse and longitudinal waves; relation between speed, wavelength and frequency;expression for displacement in wave motion;characteristics of a harmonic wave; graphicalrepresentation of a harmonic wave; amplitudeand intensity.

Review wave motion covered in Class IX. Distinction between transverse and longitudinal waves; examples; definedisplacement, amplitude, time period, frequency, wavelength and derive v=f ; graph of displacement with time/position,label time period/wavelength and amplitude,equation of a progressive harmonic(sinusoidal) wave, y = A sin (kx- t);amplitude and intensity.

(ii) Sound as a wave motion, Newton's formulafor the speed of sound and Laplace's

correction; variation in the speed of soundwith changes in pressure, temperature andhumidity; speed of sound in liquids and solids(descriptive treatment only).

Review of production and propagation of sound as wave motion; mechanical waverequires a medium; general formula for speed of sound (no derivation). ewtons formula for speed of sound in air; experimental value; Laplaces correction; calculation of value at STP; numerical problems; variation of speed v with changes in pressure, density, humidityand temperature. Speed of sound in liquidsand solids - brief introduction only. Somevalues. Mention the unit Mach 1, 2, etc.Concept of supersonic and ultrasonic.

(iii) Superimposition of waves (interference, beatsand standing waves), progressive andstationary waves.

The principle of superposition; interfer(simple ideas only); dependence of combwave form, on the relative phase of interfering waves; qualitative only - illuswith wave representations. Beats (qualitexplanation only); number of beats prod per second = difference in the frequencithe interfering waves; numerical probleStanding waves or stationary wav formation by two traveling waves (of and f same) traveling in opposite direc(ex: along a string, in an air column - inciand reflected waves); obtain y= y1+y2=[2 ym sin kx] cos( t) using equations of thtraveling waves; variation of the ampli A=2 ym sin kx with location (x) of the partinodes and antinodes; compare standwaves with progressive waves.

(iv) Laws of vibrations of stretched strings.

Equation for fundamental freq f 0=(l) T/m; sonometer, experimentaverification.

(v) Modes of vibration of strings and air columns;resonance.

Vibrations of strings and air column (clo

and open pipe); standing waves with nand antinodes; also in resonance with periodic force exerted usually by a tu fork; sketches of various nodes; fundamand overtones-harmonics; mutual relation

(vi) Doppler Effect for sound.

Doppler effect for sound; general expre for the Doppler effect when both the soand listener are moving can be given

L L r

r

v v f f v v =

which can be reduced to an

one of the four special cases, by appl proper sign convention. OTE: umerical problems are included fromtopics except where they are specifically excor where only qualitative treatment is require


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PAPER II

PRACTICAL WORK- 20 Marks

The following experiments are recommended for practical work. In each experiment, students areexpected to record their observations in tabular formwith units at the column head. Students should plot anappropriate graph, work out the necessary calculationsand arrive at the result. The teacher may alter or add.

1. Measurement by Vernier callipers. Measure thediameter of a spherical body. Calculate thevolume with appropriate significant figures.Measure the volume using a graduated cylinder and compare it with calculated value.

2. Find the diameter of a wire using a micrometer screw gauge and determine percentage error incross sectional area.

3. Determine radius of curvature of a sphericalsurface like watch glass by a spherometer.

4. Equilibrium of three concurrent coplanar forces.To verify the parallelogram law of forces and todetermine weight of a body.

5. Inclined plane: To find the downward force actingalong the inclined plane on a roller due togravitational pull of earth and to study itsrelationship with angle of inclination by plottinggraph between force and sin .

6. Friction: To find the force of kinetic friction for awooden block placed on horizontal surface and to

study its relationship with normal reaction.To determine the coefficient of friction.

7. To find the acceleration due to gravity bymeasuring the variation in time period (T) witheffective length (L) of simple pendulum; plotgraph of T s L and T 2 s L.

8. To find the force constant of a spring and to studyvariation in time period of oscillation of a bodysuspended by the spring. To find acceleration dueto gravity by plotting graph of T against m.

9. Oscillation of a simple meter rule used as bar pendulum. To study variation in time period (T)with distance of centre of gravity from axis of suspension and to find radius of gyration andmoment of inertia about an axis through the centreof gravity.

10. Boyle's Law: To study the variation in volumewith pressure for a sample of air at constanttemperature by plotting graphs between p and

V1 and between p and V.

11. Cooling curve: To study the fall in temperature of a body (like hot water or liquid in calorimeter)

with time. Find the slope of curve at four different temperatures of hot body and hencededuce Newton's law of cooling.

12. Determine Young's modulus of elasticity usingSearle's apparatus.

13. To study the variation in frequency of air columnwith length using resonance column apparatus or a long cylinder and set of tuning forks. Hencedetermine velocity of sound in air at roomtemperature.

14. To determine frequency of a tuning fork using asonometer.

15. To verify laws of vibration of strings using asonometer.

PROJECT WORK A D PRACTICAL FILE

10 Marks

Project Work 7 Marks

All candidates will do project work involving somePhysics related topics, under the guidance and regular supervision of the Physics teacher. Candidates are to

prepare a technical report formally written includingan abstract, some theoretical discussion, experimentalsetup, observations with tables of data collected,analysis and discussion of results, deductions,conclusion, etc. (after the draft has been approved bythe teacher). The report should be kept simple, butneat and elegant. No extra credit shall be given for type-written material/decorative cover, etc. Teachersmay assign or students may choose any one project of their choice.

Practical File 3 Marks

Teachers are required to assess students on the basisof the Physics practical file maintained by themduring the academic year.


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CLASS XII

There will be two papers in the subject. Paper I : Theory - 3 hour ... 70 marks Paper II : Practical - 3 hours ... 20 marks

Project Work ... 7 marks Practical File ... 3 marksPAPER I -THEORY- 70 Marks

Paper I shall be of 3 hours duration and be divided into two parts.

Part I (20 marks): This part will consist of compulsory short answer questions, testing knowledge, application and skills relating toelementary/fundamental aspects of the entire syllabus.

Part II (50 marks): This part will be divided into

three Sections A, B and C. There shall bethree questions in Section A (each carrying 9 marks) and candidates are required to answer two questions fromthis Section. There shall bethree questions in Section B (each carrying 8 marks) and candidates arerequired to answer two questions from this Section.There shall bethree questions in Section C (eachcarrying 8 marks) and candidates are required toanswer two questions from this Section. Therefore,candidates are expected to answer six questions in Part 2. ote: Unless otherwise specified, only S. I. units areto be used while teaching and learning, as well as for answering questions.

SECTIO A

1. Electrostatics

(i) Coulomb's law, S.I. unit of charge; permittivity of free space.

Review of electrostatics covered in Class X. Frictional electricity, electric charge(two types); repulsion and attraction; simpleatomic structure - electrons and protons aselectric charge carriers; conductors,insulators; quantisation of electric charge;conservation of charge; Coulomb's law(in free space only); vector form; (positioncoordinates r 1 , r 2 not necessary); SI unit of charge; Superposition principle; simplenumerical problems.

(ii) Concept of electric field E = F/q o; Gauss'theorem and its applications.

Action at a distance versus field conexamples of different fields; temperature

pressure (scalar); gravitational, electric magnetic (vector field); definition / o E F q=r r

. Electric field due to a point charge; E

r

for a group of charges (superposition); A pcharge q in an electric field E

r

experiences anelectric force E F qE =

r r

.Gauss theorem: the flux of a vector fQ=VA for velocity vector A,V

r r

the area

vector, for uniform flow of a liquid. Sim for electric field E r

, electric flux E = EA for E A

r r

and E E A = r r

for uniform E r

. For

non-uniform field E = d = . E dAr r

. Special cases for = 0 , 90 and 180 . Examples,calculations. Gauss law, statement: E =q/ 0 or E =

0

qE dA =

r r

where E is for a

closed surface; q is the net charge enclo o is the permittivity of free space. Esse properties of a Gaussian surface. Applications: 1. Deduce Coulomb's law the Gauss law and certain symmeconsiderations ( o proof required); 2 (a).excess charge placed on an isolatconductor resides on the outer surface; E

r

=0 inside a cavity in an isolated conduc(c) E = / 0 for a point outside; 3. E

r

due toan infinite line of charge, sheet of cha spherical shell of charge (inside and outsihollow spherical conductor. [Experimetest of coulombs law not included].

(iii) Electric dipole; electric field at a point on theaxis and perpendicular bisector of a dipole;electric dipole moment; torque on a dipole ina uniform electric field.

Electric dipole and dipole moment; with derivation of the E

r

at any point, (a) on the


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axis (b) on the perpendicular bisector of thedipole, for r>> 2l. [ E

r

due to continuousdistribution of charge, ring of charge, disc of charge etc not included]; dipole in uniform E

r

electric field; net force zero, torque p E =

r r r .

(iv) Electric lines of force.

A convenient way to visualize the electric field; properties of lines of force; examples of the lines of force due to an isolated point charge (+ve and - ve); dipole, two similar charges at a small distance; uniform field between two oppositely charged parallel plates.

(v) Electric potential and potential energy;

potential due to a point charge and due to adipole; potential energy of an electric dipolein an electric field. Van de Graff generator.

Brief review of conservative forces of which gravitational force and electric forces areexamples; potential, pd and potential energyare defined only in a conservative field;electric potential at a point; definitionV P =W/q0; hence V A -V B = W BA/ q0 (taking q0 from B to A) = (q/4 0 )( 1 /r A- 1 /r B ); derive thisequation; also V A = q/4 0 .1/r A ; for q>0,V A>0 and for q>d. Potential energy of a point charge (q)in an electric field E

r

, placed at a point P where potential is V, is given by U =qV and U =q (V A-V B ) . The electrostatic potential energy of a system of two charges = work done W 21=W 12 in assembling the system;U 12 or U 21= (1/4 0 ) q1q2 /r 12.For a system of 3 charges U 123 = U 12 + U 13 + U 23

=0

14

1 3 2 31 2

12 13 23

( )q q q qq qr r r + + . For a dipole

in a uniform electric field, the electric potential energy U E = - pr . E

r

, special case for =0, 900 and 1800.

Van de Graff Generator. Potential insidcharged spherical shell is uniform. A sconducting sphere of radius r and carrycharge q is located inside a large shellradius R that carries charge Q. The potendifference between the spheres, V(R) V(q/4 o ) (1/R 1/r) is independent of Q. I

two are connected, charge always flows the inner sphere to the outer sphere, raisits potential. Sketch of a very simple VaGraff Generator, its working and use.

(vi) Capacitance of a conductor C = Q/V, thefarad; capacitance of a parallel-platecapacitor; C = K 0A/d capacitors in seriesand parallel combinations; energy U = 1/2CV

2

=21 1

2 2QQV C

= .

Self-explanatory.Combinations of capacitors in series parallel; effective capacitance and chdistribution.

(vii) Dielectrics (elementary ideas only); permittivity and relative permittivity of adielectric ( r = /o). Effects on pd, chargeand capacitance.

Dielectric constant K e = C'/C; this is alsocalled relative permittivity K e = r = / o;elementary ideas of polarization of matteruniform electric field qualitative discussinduced surface charges weaken the orig field; results in reduction in E

r

and hence, in pd, (V); for charge remaining the sQ = CV = C' V' = K e . CV' ; V' = V/K e;

and e

E E K = ; if the C is kept connected w

the source of emf, V is kept constant V == Q'/C' ; Q'=C'V = K e . CV= K e . Qincreases; For a parallel plate capacitor wa dielectric in between C' = K eC = K e . o .

A/d = r . o .A/d. Then,0

r

AC d

= ;

extending this to a partially filled capacC' = o A/(d-t + t/ r). Spherical and cylindricacapacitors (qualitative only).


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2. Current Electricity

(i) Steady currents; sources of current, simplecells, secondary cells.

Sources of emf: Mention: Standard cell, solar cell, thermo-couple and battery, etc. simplecells, acid/alkali cells - qualitativedescription.

(ii) Potential difference as the power supplieddivided by the current; Ohm's law and itslimitations; Combinations of resistors in seriesand parallel; Electric energy and power.

Definition of pd, V = P/ I; P = V I;electrical energy consumed in timet is E=Pt= VIt; using ohms law

E = VIt = t RV 2 = I 2 Rt. Electric power

consumed P = VI = V 2

/R = I 2

R ; SI units;commercial units; electricity consumption and billing. Ohm's law, current density = I/A;experimental verification, graphs and slope,ohmic resistors; examples; deviations. Derivation of formulae for combination of resistors in series and parallel; special caseof n identical resistors; R p = R/n.

(iii) Mechanism of flow of current in metals, driftvelocity of charges. Resistance and resistivityand their relation to drift velocity of electrons;description of resistivity and conductivity

based on electron theory; effect of temperature on resistance, colour coding of resistance.

Electric current I = Q/t; atomic view of flow of electric current in metals; I=vd ena. Electron theory of conductivity; accelerationof electrons, relaxation time ;derive = ne2 /m and = m/ne2 ; effect of temperature on resistance. Resistance R= V/I for ohmic substances; resistivity , given by R= .l/A; unit of is .m; conductivity =1/ ; Ohms law as J

r

= E r

; colour coding of resistance.

(iv) Electromotive force in a cell; internalresistance and back emf. Combination of cellsin series and parallel.

The source of energy of a seat of emf (sua cell) may be electrical, mechanical, theor radiant energy. The emf of a sourcdefined as the work done per unit charg force them to go to the higher poin potential (from -ve terminal to +ve terminside the cell) so, = dW /dq; but dq = Idt

dW = dq = Idt . Equating total work doto the work done across the external resi R plus the work done across the interesistance r; Idt=I 2 R dt + I 2rdt; =I (R + r); I= /( R + r ); also IR +Ir = or V= - Ir where Ir is called the back emf as it against the emf ; V is the terminal pd Derivation of formula for combination ofin series, parallel and mixed grouping.

(v) Kirchhoff's laws and their simple applicationsto circuits with resistors and sources of emf;Wheatstone bridge, metre-bridge and

potentiometer; use for comparison of emf anddetermination of internal resistance of sourcesof current; use of resistors (shunts andmultipliers) in ammeters and voltmeters.

Statement and explanation with simexamples. The first is a conservation lawcharge and the 2nd is law of conservation oenergy. ote change in potential acrosresistor V=IR0 if we go up against tcurrent across the resistor. When we through a cell, the -ve terminal is at a lolevel and the +ve terminal at a higher le so going from -ve to +ve through the celare going up and V=+ and going from +veto -ve terminal through the cell we are gdown, soV = - . Application to simplcircuits. Wheatstone bridge; right in beginning take I g =0 as we consider abalanced bridge, derivation of R1 /R2 = R3 /R4is simpler [Kirchhoffs law not necessaMetre bridge is a modified form Wheatstone bridge. Here R2 = l 1 p and R4 =l 2

p; R1 /R3 = l 1 /l 2 . Potentiometer: fall in potential V l - conditions; auxiliary em 1 is balanced against the fall in potentia1 across length l 1 . 1 = V 1 =Kl 1 ; 1 / 2 = l 1 /l 2; potentiometer as a voltmeter. Pote gradient; comparison of emfs; determinof internal resistance of a cell. Conversio


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galvanometer to ammeter and voltmeter and their resistances.

(vi) Heating effect of a current (Joule's law).

Flow of electric charge (current) in aconductor causes transfer of energy from the source of electricity (may be a cell or

dynamo), to the conductor (resistor), asinternal energy associated with the vibrationof atoms and observed as increase intemperature. From the definition of pd,V=W/q; W =U = qV = VIt. The rate of energy transfer U/t = VI or power P = VI = I 2 R=V 2 /R using Ohm's law. This is Joule,s law. This energy transfer is called Joule heating. SI unit of power. Experimental verification of Joules law.

(vii) Thermoelectricity; Seebeck effect;measurement of thermo emf; its variation withtemperature. Peltier effect. Discovery of Seebeck effect. Seebeck series; Examples with different pairs of metals (for easy recall remember - hot cofe and ABC - from copper to iron at the hot junction and from antimony to bismuth at the cold junction for current directions in thermocouple);variation of thermo emf with temperaturedifferences, graph; neutral temperature,temperature of inversion; slope:thermoelectric power = + 1/2 2 (noderivation), S = d /d = + . Thecomparison of Peltier effect and Joule effect.

3. Magnetism

(i) Magnetic field Br

, definition from magneticforce on a moving charge; magnetic fieldlines. Superposition of magnetic fields;magnetic field and magnetic flux density; theearth's magnetic field; Magnetic field of amagnetic dipole; tangent law.

Magnetic field represented by the symbol Bis

now defined by the equationo

F q V =

r r

x B

r

(which comes later under subunit 4.2; Br

isnot to be defined in terms of force acting on aunit pole, etc; note the distinction of B

r

from E

r

is that Br

forms closed loops as there areno magnetic monopoles, whereas E

r

lines

start from +ve charge and end on -ve chaMagnetic field lines due to a magnetic d(bar magnet). Magnetic field in end-on broadside-on positions ( o derivatioMagnetic flux B = B

r

. Ar

= BA for B uniformand B

r

Ar

; i.e. area held perpendicular t

Br

. For = BA( Br

Ar

); B= /A is the fluxdensity [SI unit of flux is weber (Wb)]note that this is not correct as a definequation as B

r

is vector and and /A are scalars, unit of B is tesla (T) equa10-4 gauss. For non-uniform B

r

field, = d = B

r

.dAr

. Earth's magnetic field Br

E is uniform over a limited area like that lab; the component of this field in horizontal directions B H is the one effectivelacting on a magnet suspended or pivohorizontally. An artificial magnetic fiel produced by a current carrying loop (see B

r

c , or a bar magnet Br

m in the horizontal plane with its direction adj perpendicular to the magnetic meridian;is superposed over the earth's fields B

r

H which is always present along the magnmeridian. The two are then perpendiculaeach other; a compass needle experienctorque exerted by these fields and comes equilibrium position along the resultant

making an angle withwith B H . Then Bc-or Bm =B H tan. This is called tangent law Deflection Magnetometer, description, seand its working.

(ii) Properties of dia, para and ferromagneticsubstances; susceptibility and relative

permeability

It is better to explain the main distinctioncause of magnetization (M) is due to magdipole moment (m) of atoms, ions molecules being 0 for dia, >0 but very s

for para and > 0 and large for ferromagnmaterials; few examples; placed in exte B

r

, very small (induced) magnetization direction opposite to B

r

in dia, small magnetization parallel to B

r

for para, and large magnetization parallel to B

r

for


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ferromagnetic materials; this leads to linesof B

r

becoming less dense, more dense and much more dense in dia, para and ferro,respectively; hence, a weak repulsion for dia,weak attraction for para and strong attraction for ferro - - - - - also a small bar suspended inthe horizontal plane becomes perpendicular to the B

r

field for dia and parallel to Br

for para and ferro. Defining equation H = (B/ 0 )-M; the magnetic properties, susceptibility m = (M/H) < 0 for dia (as M is opposite H)and >0 for para, both very small, but verylarge for ferro; hence relative permeability r =1+ m < 1 for dia, > 1 for para and >>1(very large) for ferro; further, m 1/T (Curies law) for para, independent of temperature (T) for dia and depends on T ina complicated manner for ferro; on heating

ferro becomes para at Curie temperature.4. Electromagnetism

(i) Oersted's experiment; Biot-Savart law, thetesla; magnetic field near a long straight wire,at the centre of a circular loop, and at a pointon the axis of a circular coil carrying currentand a solenoid. Amperes circuital law and itsapplication to obtain magnetic field due to along straight wire; tangent galvanometer.

Only historical introduction throughOersteds experiment. [Amperes swimming rule not included]. Biot-Savart law in vector form; application; derive the expression for B(i) near a very long wire carrying current;direction of B

r

using right hand (clasp) rule-no other rule necessary; (ii) at the centre of acircular loop carrying current; (iii) at any point on its axis. Current carrying loop as amagnetic dipole. Amperes Circuital law: statement and brief explanation. Apply it toobtain B

r

near a long wire carrying current.Tangent galvanometer- theory, working, use,

advantages and disadvantages.(ii) Force on a moving charge in a magnetic field;

force on a current carrying conductor kept in amagnetic field; force between two parallelcurrent carrying wires; definition of theampere based on the force between two

current carrying wires. Cyclotron (simpleidea).

Lorentz force equation . B F q v B= r r

r ; special cases, modify this equ substituting dt l d / for v and I for q/dt to yie

F

r

= I dl

r

B

r

for the force acting on current carrying conductor placed in a Br

field. Derive the expression for force bettwo long parallel wires carrying curreusing Biot-Savart law and F

r

= I dl r

Br

;define ampere the base unit of SI and hecoulomb from Q = It. Simple ideas abworking of a cyclotron, its principle, limitations.

(iii) A current loop as a magnetic dipole; magneticdipole moment; torque on a current loop;moving coil galvanometer.

Derive the expression for torque on a cucarrying loop placed in a uniform B

r

, using F = IlB and = F r = IAB sin for turns =m xB where the dipole momem = A NI unit: A.m2. A current carrying loois a magnetic dipole; directions of cuand B

r

and mr using right hand rule only; other rule necessary. Mention orbital magmoment of electrons in Bohr model of HMoving coil galvanometer; construc principle, working, theory I= k ,advantagesover tangent galvanometer.

(iv) Electromagnetic induction, magnetic flux andinduced emf; Faraday's law and Lenz's law;transformers; eddy currents.

Magnetic flux, change in flux, rate of chof flux and induced emf; Faradays = -d /dt, [only one law represented by equation]. Lenz's law, conservation of enemotional emf = Blv, and power P = (Blv)2 /R; eddy currents (qualitativtransformer (ideal coupling), principworking and uses; step up and step doenergy losses.

(v) Mutual and self inductance: the henry.Growth and decay of current in LR circuit(dc) (graphical approach), time constant.


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Mutual inductance, illustrations of a pair of coils, flux linked 2 = MI 1; induced emf

22

d dt = =M 1dI

dt . Definition of M as

M =1

21

2 M I or

dt

dI = . SI unit henry.

Similar treatment for L dt dI = ;

henry = volt. second/ampere [expressions for coefficient of self inductance L and mutual inductance M, of solenoid/coils and experiments, not included]. R-L circuit;induced emf opposes changes, back emf is set up, delays starting and closing, graphical representation of growth and decay of current in an R-L circuit [no derivation]; define and explain time constant from the graph; =L/R(result only). Unit of = unit of time = second. Hence, this name Time Constant.

(vi) Simple a.c. generators. Principle, description, theory and use.

(v) Comparison of a.c. with d.c.Variation in current and voltage with time for a.c. and d.c.

5. Alternating Current Circuits

(i) Change of voltage and current with time, the

phase difference; peak and rms values of voltage and current; their relation insinusoidal case.

Sinusoidal variation of V and I with time, for the output from an ac generator; time period, frequency and phase changes; rms value of V and I in sinusoidal cases only.

(ii) Variation of voltage and current in a.c.circuits consisting of only resistors, onlyinductors and only capacitors (phasor representation), phase lag and phase lead.

May apply Kirchhoffs law and obtain simpledifferential equation (SHM type), V = Vo sin t, solution I = I 0 sin t, I 0 sin ( t + /2) and I 0 sin ( t - /2) for pure R, C and L circuits,respectively. Draw phase (or phasor)diagrams showing voltage and current and

phase lag or lead; resistance R, inducreactance X L , X L= L and capacitativereactance X C , X C = 1/ C and their mutualrelations. Graph of X Land X C vs f.

(iii) The LCR series circuit: phasor diagram,expression for V or I; phase lag/lead;impedance of a series LCR circuit (arrived at

by phasor diagram); Special cases for RL andRC circuits.

RLC circuit in single loop, note the pd a R, L and C; [the more able students may Kirchhoffs law and obtain the differeequation]. Use phasor diagram methodobtain expression for I or V and the net plag/lead; use the results of 5(ii), V lags

/2 in a capacitor, V leads I by /2 in aninductor, V and I are in phase in a resistois the same in all three; hence draw phdiagram, combine V L and Vc (in opposite phase; phasors add like vectors) to V=V R+V L+V C (phasor addition) and the mavalues are related by V 2m=V 2 RM +(V Lm-V Cm )2 .Substituting pd=current x resistance reactance, we get Z 2= R2+(X L-X c )2and tan = (V L m-V Cm )/V Rm= (X L-X c )/R giving I = I m

sin (wt- ) where I m =V m /Z etc. Special case for RL and RC circuits. Graph of Z vs f.

(iv) Power P associated with LCR circuit= 1/2VoIo cos =V rmsIrms cos; power absorbedand power dissipated; choke coil (choke andstarter); electrical resonance; oscillations in anLC circuit ( = 1/ LC).

Average power consumed averaged ov full cycle P =(1/2) m. I m cos . Power factor cos = R/Z. Special case for pure R , L,choke coil:- X L controls current but cos = 0,hence P =0; LC circuit; at resonance wi X L=X c , Z=Z min= R, power delivered to circuby the source, is maximum; 2 = 1/LC;

f = 2

.


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SECTIO B

6. Wave Optics

(i) Complete electromagnetic spectrum fromradio waves to gamma rays; transverse natureof electromagnetic waves, Huygen's principle;laws of reflection and refraction from

Huygen's principle. Speed of light.Qualitative descriptions only, but some wavelength range values may be noted; common features of all regions of em spectrumincluding transverse nature ( E

r

and Br

perpendicular toC

r

); special features of thecommon classification (gamma rays, X rays,UV rays, visible spectrum, IR, microwaves,radio and TV waves) in their production(source), propagation, modulation and demodulation (qualitative only) AM and FM, interaction with matter, detection and other properties; uses; approximate range of or f or at least proper order of increasing f or . Huygens principle: wavefronts -different types/shapes, rays: Huygensconstruction and Huygens principle; proof of laws of reflection and refraction using this.[Refraction through a prism and lens on thebasis of Huygens theory: ot required].Michelsons method to determine the speed of light.

(ii) Conditions for interference of light,interference of monochromatic light bydouble slit; measurement of wave length.Fresnels biprism.

Phase of wave motion; superposition of identical waves at a point, path difference and phase difference; coherent and incoherent light waves; interference- constructive and destructive, conditions for sustained interference of light waves [mathematical deduction of interference from the equationsof two progressive waves with a phasedifference is not to be done]. Young's double slit experiment, set up, diagram, geometrical deduction of path difference = d sin ,between waves (rays) from the two slits; using =n for bright fringe and (n+) for dark fringe and sin = tan =yn /D as y and are small, obtain yn=(D/d)n and fringe width =(D/d) etc. Experiment of Fresnel biprism

(qualitative only). Measurement of using a

telescope; determination of , using d D = .

(iii) Single slit Fraunhoffer diffraction (elementaryexplanation).

Diffraction at a single slit experimental sdiagram, diffraction pattern, position secondary maxima, conditions for seconmaxima, a sin n =(2n+1) /2, for secondaryminima a sin n= n , where n = 1,2,3 distribution of intensity with angular distaangular width of central bright frinMention diffraction by a grating and its udetermining wave length of light (Detailrequired).

(iv) Plane polarised electromagnetic wave(elementary idea), polarisation of light byreflection. Brewster's law; polaroids.

Review description of an electromagwave as transmission of energy by perichanges in E

r

and Br

along the path;transverse nature as E

r

and Br

are perpendicular toC

r

(velocity). These threvectors form a right handed system, so E

r

x Br

is along C r

, they are mutuall perpendicular to each other. For ordinlight, E

r

and Br

are in all directions in a plane perpendicular to theC

r

vector-unpolarised waves. If E

r

and (hence Br

also)is confined to a single line only ( C

r

, we havelinearly polarized light. The plane contai E

r

(or Br

) and C r

remains fixed. Hence, linearly polarised light is also called pl polarised light. Plane of polarisa polarisation by reflection; Brewsters tan i p=n; refracted ray is perpendicular reflected ray for i = i p; i p+r p = 90 ; polaroids; use in production detection/analysis of polarised light., ouses.

7. Ray Optics and Optical Instruments for

(i) Refraction of light at a plane interface (Snell'slaw); total internal reflection and criticalangle; total reflecting prisms and opticalfibres.


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Self-explanatory. Simple applications;numerical problems included.

(ii) Refraction through a prism, minimumdeviation and derivation of relation betweenn, A and min. Include explanation of i- graph, i1 = i2 = i

(say) for m; from symmetry r 1 = r 2; refracted ray inside the prism is parallel to the base of the prism; application to triangular prismswith angle of the prism 300 , 450 , 600 and 900 respectively; ray diagrams.

(iii) Refraction at a single spherical surface(relation between n 1, n2, u, v and R);refraction through thin lens (lens maker'sformula and formula relating u, v, f, n, R 1 andR 2); combined focal length of two thin lensesin contact. Combination of lenses [Silveringof lens excluded].

Self-explanatory. Limit detailed discussion to one case only-convex towards rarer medium, for spherical surface and real image. For lens, derivationonly for biconvex lens with R1= R2; extend theresults to biconcave lens, plano convex lensand lens immersed in a liquid; do also power of a lens P=1/f with SI unit dioptre. For lenses in contact 1/F= 1/f 1+1/f 2 and P=P 1+P 2. Formation of image and determination of focal length with combination of thin lenses.

(iv) Dispersion; dispersive power; production of pure spectrum; spectrometer and its setting(experimental uses and procedures included);absorption and emission spectra; spherical andchromatic aberration; derivation of conditionfor achromatic combination of two thin lensesin contact and not of prism.

Angular dispersion; dispersive power,conditions for pure spectrum; spectrometer with experiments for A and . Hence, m and n; rainbow - ray diagram (no derivation).Simple explanation. Spectra: emission spectra; line; band and continuous spectra-their source and qualitative explanation;absorption spectra - condition; solar spectrumand Fraunhoffer lines, spherical aberration ina convex lens (qualitative only), how to reducelinear or axial chromatic aberration,

derivations, condition for achromcombination of two lenses in contact.

(v) Simple microscope; Compound microscopeand their magnifying power.

For microscope - magnifying power for imat least distance of distinct vision and

infinity; ray diagrams, numerical problincluded.(vi) Simple astronomical telescope (refracting and

reflecting), magnifying power and resolving power of a simple astronomical telescope.

Ray diagrams of reflecting as welrefracting telescope with image at infionly; simple explanation; magnifying poresolving power, advantages, disadvantaand uses.

SECTIO C

8. Electrons and Photons

(i) Cathode rays: measurement of e/m for electrons. Millikans oil drop experiment.

Production of cathode rays only briefqualitative [historical details not includThomsons experiment to measure e/melectrons: e/m=(V) (E/B)2.Thermionic emission, deflection of cha

particle by E

r

and B

r

, and fluorescenc produced by electron. Millikans oil experiment - quantization of charge.

(ii) Photo electric effect, quantization of radiation; Einstein's equation; thresholdfrequency; work function; energy andmomentum of photon. Determination of Plancks Constant.

Experimental facts; do topics as given; Einstein used Plancks ideas and extendto apply for radiation (light); photoelec

effect can be explained only assumquantum (particle) nature of radiatiTheory and experiment for determinatio Plancks constant (from the graph of stop potential V versus frequency f of the inclight). Momentum of photon p=E/c=hf/c= .


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(iii) Wave particle duality, De Broglie equation, phenomenon of electron diffraction(informative only).

Dual nature of radiation already discussed;wave nature in interference, diffractionand polarization; particle nature in photoelectric effect and Compton effect. Dual nature of matter: particle nature common inthat it possess momentum p=mv and kineticenergy K=mv2. The wave nature of matter was proposed by Louis de Broglie =h/p=h/mv. Davisson and Germer experiment;qualitative description and discussion of theexperiment, polar graph. o numerical problem.

9. Atoms

(i) Charge and size of nuclei ( -particlescattering); atomic structure; Bohr's

postulates, Bohr's quantization condition; radiiof Bohr orbits for hydrogen atom; energy of the hydrogen atom in the nth state; linespectra of hydrogen and calculation of E and f for different lines.

Rutherfords nuclear model of atom(mathematical theory of scattering excluded),based on Geiger - Marsden experiment on -scattering; nuclear radius r in terms of closest approach of particle to the nucleus,obtained by equating K= mv2 of the particle to the change in electrostatic

potential energyU of the system[(1/4 0(2e)(Ze)/r 0 ]; r 0 10-15m =1 fm or 1 fermi; atomic structure; only general qualitative ideas, including, atomic number Z, eutron number and mass number A. Abrief account of historical background leading to Bohrs theory of hydrogen spectra;empirical formula for Lyman, Balmer and Paschen series. Bohrs model of H atom, postulates (Z=1); expressions for orbital velocity, kinetic energy, potential energy,radius of orbit and total energy of electron. Energy level diagram for n=1,2,3calculation of E, frequency and wavelengthof different lines of emission spectra;agreement with experimentally observed values. [Use nm and not for unit of ].

(ii) Production of X-rays; maximum frequencyfor a given tube potential. Characteristic andcontinuous X -rays. Mosleys law.

A simple modern X-ray tube main partscathode, heavy element target kept coolanode, all enclosed in a vacuum tuelementary theory of X-ray production; eof increasing filament current- temperaincreases rate of emission of electrons (the cathode), rate of production of X rays

hence, intensity of X rays increases (no frequency); increase in anode poteincreases energy of each electron, each X photon and hence, X-ray frequency (Emaximum frequency hf max=eV; continuous spectrum of X rays has minimum wavel min= c/f max. Mosleys law. Characteristand continuous X-rays; origin.

10. uclei

(i) Atomic masses; unified atomic mass unit uand its value in MeV; the neutron;

composition and size of nucleus; mass defectand binding energy.

Atomic masses; unified atomic mass symbol u, 1u=1/12 of the mass of C 12 atom =1.66x10-27 kg). Composition of nucleus; mdefect and binding energy BE=( m)c2.Graph of BE/nucleon versus mass numb special features - low for light as weheavy elements. Middle order more st[see fission and fusion in 11.(ii), 11.(iii)].

(ii) Radioactivity: nature and radioactive decay

law, half-life, mean life and decay constant. Nuclear reactions.

Discovery; spontaneous disintegration oatomic nucleus with the emission of or particles and radiation, unaffected byordinary chemical changes. Radioacdecay law; derivation of = oe- t ; half life period T; graph of versus t, with T maon the X axis. Relation between T an ;mean life and . Value of T of some commradioactive elements. Examples of nuclear reactions with conservation nucleon number and charge. (neutrino tincluded.

[Mathematical theory of and decay not included]. Changes taking place withinnucleus included.


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11. uclear Energy

(i) Energy - mass equivalence.

Einsteins equation E=mc2. Somecalculations. (already done under 10.(i));mass defect/binding energy, mutual annihilation and pair production as examples.

(ii) Nuclear fission; chain reaction; principle of operation of a nuclear reactor.

(iii) Nuclear fusion; thermonuclear fusion as thesource of the sun's energy.

Theoretical (qualitative) prediction of exothermic (with release of energy) nuclear reaction, in fusing together two light nuclei to form a heavier nucleus and in splitting heavynucleus to form middle order (lower massnumber) nucleus, is evident from the shape of BE per nucleon versus mass number graph. Also calculate the disintegration energy Q for a heavy nucleus (A=240) with BE/A 7.6 MeV per nucleon split into two equal halveswith A=120 each and BE/A 8.5MeV/nucleon; Q 200 MeV. Discovery of fission. Any one equation of fission reaction.Chain reaction- controlled and uncontrolled;nuclear reactor and nuclear bomb. Main parts of a nuclear reactor including a simplediagram and their functions - fuel elements,moderator, control rods, coolant, casing;criticality; utilization of energy output - all qualitative only. Fusion, simple example of 4 1 H 4 He and its nuclear reaction equation;requires very high temperature 106 degrees; difficult to achieve; hydrogen bomb;thermonuclear energy production in the sunand stars. [Details of chain reaction not required].

12. Semiconductor Devices

(i) Energy bands in solids; energy band diagramsfor distinction between conductors, insulators

and semi-conductors - intrinsic and extrinsic;electrons and holes in semiconductors.

Elementary ideas about electrical conductionin metals [crystal structure not included]. Energy levels (as for hydrogen atom), 1s, 2s,2p, 3s , etc. of an isolated atom such as that of copper; these split, eventually forming

bands of energy levels, as we consider copper made up of a large number of isolatoms, brought together to form a lattdefinition of energy bands - groups of cl spaced energy levels separated by band called forbidden bands. An idealirepresentation of the energy bands fo

conductor, insulator and semiconduccharacteristics, differences; distinctbetween conductors, insulators a semiconductors on the basis of energy bwith examples; qualitative discussion oenergy gaps (eV) in typical substan(carbon, Ge, Si); some electrical properti semiconductors. Majority and micharge carriers - electrons and holeintrinsic and extrinsic, doping, p-type, n-donor and acceptor impurities. [ o nume problems from this topic].

(ii) Junction diode; depletion region; forward andreverse biasing current - voltagecharacteristics; pn diode as a half wave and afull wave rectifier; solar cell, LED and

photodiode. Zener diode and voltageregulation.

Junction diode; symbol, simple qualidescription only [details of different typ formation not included]. The topics areexplanatory. [Bridge rectifier of 4 diodes

included]. Simple circuit diagram and gra function of each component - in the elecircuits, qualitative only. Elementary idea solar cell, photodiode and light emitting d(LED) as semi conducting diodes. explanatory.

(iii) The junction transistor; npn and pnptransistors; current gain in a transistor;transistor (common emitter) amplifier (onlycircuit diagram and qualitative treatment) andoscillator.

Simple qualitative description of constru- emitter, base and collector; npn and type; symbol showing directions of curreemitter-base region (one arrow only)- banarrow; current gain in transistor; commemitter configuration only, characterist I B vs V BE and I C vs V CE with circuit


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diagram; no numerical problem; commonemitter transistor amplifier - correct diagram; qualitative explanation including amplification, wave form and phase reversal.[relation between , not included, nonumerical problems]. Circuit diagram and qualitative explanation of a simple oscillator.

(iv) Elementary idea of discreet and integratedcircuits, analogue and digital circuits. Logicgates (symbols; working with truth tables;applications and uses) - NOT, OR, AND,

NOR, NAND.

Self explanatory. Advantages of IC. Introduction to elementary digital electronics. Logic gates as given; symbols, input and output, Boolean equations (Y=A+B etc), truthtable, qualitative explanation. [ o numerical

problems. Realisation not included].PAPER II

PRACTICAL WORK- 20 Marks

The experiments for laboratory work and practicalexaminations are mostly from two groups;(i) experiments based on ray optics and(ii) experiments based on current electricity.The main skill required in group (i) is to remove

parallax between a needle and the real image of another needle. In group (ii), understanding circuitdiagram and making connections strictly following thegiven diagram is very important. Take care of

polarity of cells and meters, their range, zero error,least count, etc. A graph is a convenient and effectiveway of representing results of measurement.Therefore, it is an important part of the experiment.Usually, there are two graphs in all question papers.Students should learn to draw graphs correctly notingall important steps such as title, selection of origin,labelling of axes (not x and y), proper scale and theunits given along each axis. Use maximum area of graph paper, plot points with great care, mark the

points plotted with or and draw the best fitstraight line (not necessarily passing through all the

plotted points), keeping all experimental pointssymmetrically placed (on the line and on the left andright side of the line) with respect to the best fit thinstraight line. Read intercepts carefully. Y intercepti.e. y 0 is that value of y when x = 0. Slope m of the

best fit line should be found out using two distant points, one of which should be unplotted point, using

2 1

2 1

y ym x x

=

.

OTE:

Short answer questions may be set from each

experiment to test understanding of theory and logicof steps involved.

The list of experiments given below is only a generalrecommendation. Teachers may add, alter or modifythis list, keeping in mind the general pattern of questions asked in the annual examinations.

1. Draw the following set of graphs using data fromlens experiments -

i) against u. It will be a curve.

ii) Magnificationvum

= against and to find

focal length by intercept.

iii) y = 100/v against x = 100/u and to find f by intercepts.

2. To find f of a convex lens by using u-v method.

3. To find f of a convex lens by displacementmethod.

4. Coaxial combination of two convex lenses not incontact.

5. Using a convex lens, optical bench and two pins,obtain the positions of the images for various

positions of the object; f


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10. Set up a deflection magnetometer in Tan-A position, and use it to compare the dipolemoments of the given bar magnets, using(a) deflection method, neglecting the length of themagnets and (b) null method.

11. Set up a vibration magnetometer and use it tocompare the magnetic moments of the given bar magnets of equal size, but different strengths.

12. Determine the galvanometer constant of a tangentgalvanometer measuring the current (using anammeter) and galvanometer deflection, varyingthe current using a rheostat. Also, determine themagnetic field at the centre of the galvanometer coil for different values of current and for different number of turns of the coil.

13. Using a metre bridge, determine the resistance of about 100 cm of constantan wire, measure itslength and radius and hence, calculate the specific

resistance of the material.14. Verify Ohms law for the given unknown

resistance (a 60 cm constantan wire), plotting agraph of potential difference versus current. Fromthe slope of the graph and the length of the wire,calculate the resistance per cm of the wire.

15. From a potentiometer set up, measure the fall in potential for increasing lengths of a constantanwire, through which a steady current is flowing;

plot a graph of pd V versus length l. Calculate the potential gradient of the wire. Q (i) Why is the

current kept constant in this experiment? Q (ii)How can you increase the sensitivity of the

potentiometer? Q (iii) How can you use the aboveresults and measure the emf of a cell?

16. Compare the emf of two cells using a potentiometer.

17. To study the variation in potential drop withlength of slide wire for constant current, hence todetermine specific resistance.

18. To determine the internal resistance of a cell by potentiometer device.

19. Given the figure of merit and resistance of agalvanometer, convert it to (a) an ammeter of range, say 2A and (b) a voltmeter of range 4V.Also calculate the resistance of the new ammeter and voltmeter.

20. To draw I-V characteristics of a semi-conductor diode in forward and reverse bias.

21. To draw characteristics of a Zener diode and todetermine its reverse breakdown voltage.

22. To study the characteristics of pnp/npn transistor in common emitter configuration.

PROJECT WORK A D PRACTICAL FILE 10 Marks

Project Work 7 Marks

The Project work is to be assessed by a VisitingExaminer appointed locally and approved by theCouncil.

All candidates will do project work involving some physics related topics, under the guidance and regular supervision of the Physics teacher.

Candidates are to prepare a technical report formallywritten including an abstract, some theoreticaldiscussion, experimental setup, observations withtables of data collected, analysis and discussion of results, deductions, conclusion, etc. (after the draft has

been approved by the teacher). The report should bekept simple, but neat and elegant. No extra credit shall be given for typewritten material/decorative cover,etc. Teachers may assign or students may choose anyone project of their choice.

Practical File 3 Marks

The Visiting Examiner is required to assess studentson the basis of the Physics practical file maintained bythem during the academic year.

Documents

19. ISC Physics