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CNS: GEAS 2

1. Which of the following radiations will produce electron with highest energy?

A. Visible Light C. X-rays

B. Ultraviolet light D. Gamma rays

ANSWER: Gamma Rays

2. Two twins are 25 years old when one of them sets out on a journey through

space at nearly constant speed. The twin in the spaceship measures time with anaccurate watch. When he returns to earth, he claims to be 31 years old, while th

twin left is then 43 years old. What was the speed of the spaceship?

A. 3.83x108m/s C. 2.8383x108m/s

B. 1.5683x108m/s D. 4.5383x108m/s

SOLUTION:

The spaceship clock reads the trip to be only 6 years long, while the eart

clock reads it to be 18 years. Then using time dilation formula:

2

c

v1stmt

= ; mt = time moving clock

; st = time of stationary clock

2

c

v1186

=

v = 0.943c

v = 2.83x108m/s

ANSWER: 2.83x108m/s

3. The flow of heat from a hot to a cold body is an example of

A. adiabatic process C. reversible process

B. irreversible process D. isothermal process

ANSWER: irreversible process

4. How fast is an object moving if its apparent mass is to be 1 percent larger

than its rest mass.

A. 4.2x107m/s C. 5.2x107m/s

B. 2.2x107m/s D. 3.2x107m/s

SOLUTION:

We make use of the formula2

o

c

v1

mm

= to obtain

0.98032

o1.01m

om2

m

om2

c

v1 =

=

=

Solving gives v = 0.14c = 4.2x107m/s

ANSWER: 4.2x107m/s

5. A heat engine with 100% of efficiency would have to

A. do no work C. use no heat

B. be at a uniform temperature D. discharge at 0C

ANSWER: discharge at 0C

6. The process in which no heat enters or leaves the system is termed as

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A. isochoric C. isothermal

B. isobaric D. adiabatic

ANSWER: adiabatic

7. Two reversible engines A and B have their sources at 800 and 640K. Their sink

are at 400K and 300K respectively

A. A is more efficient than B

B. A is less efficient than B

C. They are equally efficient

D. Their efficiencies depend only upon the type of fuels usedANSWER: A is less efficient than B

8. A hole is to be punched out of a plate having an ultimate shearing stress of

300MPa. If the compressive stress in the punch is limited to 400MPa. Determine

the maximum thickness of plate from a hole 100mm in diameter can be punched.

A. 22.23 mm C. 33.33 mm*

C. 23.44 mm D. 42.55 mm

SOLUTION:

A

PS= Stress

( )( )400

4

2100rASP

==

P= 1,000,000r N

From shearing of plate:

( )( )

33.33mmt

30010001,000,000

sSsAP

100rtrDtsA

=

=

=

==

ANSWER: 33.33 mm

9. A cylindrical pressure vessel is fabricated from steel plates which have

thickness of 20 mm. The diameter of the pressure vessel is 500 mm and its length

is 3 m. Determine the maximum internal pressure which can be applied if the

stress in the steel is limited to 140 MPa.

A. 12.4 MPa C. 11.2 MPa

B. 15.6 MPa D. 17.9 MPa

SOLUTION:

( )( )

( )11.2MPa

30020

750,000140

A

PS

750,000T

1,500,000F2T

N1,500,000F

3000500DLF

=

=

=

=

==

=

==

ANSWER: 11.2 MPa

10. Compute the apparent mass of an electron traveling at half the speed of

light.

A. 1.05x10-30kg C. 2.05 x10-30kg

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B. 1.50 x10-30kg D. 2.50 x10-30kg

SOLUTION:

The rest mass of an electron is 9.1 x10-31kg. Then

( )

kg31

101.05m

0.866

kg-31

109.1

20.51

om

2

c

0.5c1

om

2

c

v1

omm

=

=

=

=

=

ANSWER: 1.05x10-30kg

11. Compute the speed of sound in neon gas at 27C. For neon, N=20.18kg/kmol.

A. 293 m/s C. 454 m/s

B. 156 m/s D. 544 m/s

SOLUTION:

Neon being monoatomic gas, has 67.1=

Thus,

( )( )( )

454m/sv

ol20.18kg/km

300KK8314J/kmol1.67

M

RTv

=

==

ANSWER: 454 m/s

12. The volume strain for a constqatn applied force increases directly with an

increase in

A. volume C. surface area

B. compressibility D. bulk modulus

ANSWER: compressibility

13. An explosion occurs at a distance of 6.0 km from a person. How long after th

esplosion does the person hear it? Assume the temperature is 14C.

A. 12.6 s C. 17.6 s

B. 21.5 s D. 10.7 s

SOLUTION:

Because the speed of sound increases by 0.61 m/s for each C rise in

temperature, we have

v = 331 m/s + 0.61(14)

v = 640 m/s

Using s = vt, we find that the time taken is

17.6s340s

6000m

v

st ===

ANSWER: 17.6 s

14. A property of matter that is often used by chemis as an identification tag

for s asubstance.

A. mass C. volume

B. specific gravity D. density

ANSWER: density

15. The mass of an alpha particle is how many times more than that of the

electron?

A. 3500 times C. 1400 times

B. 7300 times D. 6300 times

ANSWER: 7300 times

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16. What kind of chemical bond will form in binary compounds where the

electronegativity difference between atoms is greater than 2.0?

A. metallic bond C. ionic bond

C. covalent bon D. mechanical bond

ANSWER: Ionic Bond

17. What kind of chemical bond will form in binary compounds where the

electronegativity difference between atoms is less than 1.5?

A. metallic bond C. ionic bondB. covalent bond D. mechanical bond

ANSWER: Covalent Bond

18. If the indeterminate error in weighing on a laboratory balance is 0.003 g.

What size sample should you take to keep the relative error to 1.0%?

A. 0.03 g C. 0.30 g

B. 1.30 g D. 2.03 g

ANSWER: 0.30 g of sampleSOLUTION:

sampleofg0.30X

sampleofgX

g0.0030

100

1

100%weightinpartstotal

weightinpart1errorRelative1.0%

=

=

=

19. What type of stress is produced whenever the applied load cause one section

of a body to tend to slide past its adjacent section?

A. normal stress C. sliding stress

B. shearing stress* D. bearing stress

ANSWER: shearing stress

20. The actual stress that the material has when under load is called:

A. allowable stress C. working stress

B. proportional limit D. rupture stressANSWER: working stress

21. What type of deformation is caused by shearing stress?

A. change in area C. change in shape

B. change in volume D. angular change

ANSWER: change in shape

22. The straight-line portion of stress-strain is actually a measure of ______ o

the material.

A. elasticity C. stiffness

B. stress D. strain

ANSWER: stiffness

23. Who coined the term energy in 1807?

A. Thomas Young C. Lord Kelvin

B. William Thompson D. William Rankine

ANSWER: Thomas Young

24. A process during which the entropy remains constant:

A. isentropic process C. polytropic process

B. entropic process D. endothermic process

ANSWER: isentropic process

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25. A pure substance at absolute zero temperature is in perfect order, and its

entropy is zero. This is known as:

A. the zeroth law of thermodynamics C. the third law of

thermodynamics

B. first law of thermodynamics D. second law of thermodynamics

ANSWER: third law of thermodynamics

26. A steel rod is stretched between two rigid walls and carries a tensile load

of 5000 N at 20C. If the allowable stress is not to exceed 130 MPa at -20C,

what is the minimum diameter of the rod? Assume = 11.7 m/m-C and E = 200GPaA. 12.33 mm C. 13.22 mm

B. 14.55 mm D. 16.22 mm

SOLUTION:

( )

( )( )( )

mm13.22d

mm137.44

d

mm137.4A

10200A

5000401011.7

10200

130

AE

PLTL

E

SL

yyy

22

2

3

6

3

LT

=

=

=

+=

+=

+=

ANSWER: 13.22 mm

27. A solid shaft 5 m long and 104 mm in diameter is stressed to 60 MPa when

twisted through 4. Using G = 83 GPa, what power can be transmitted by the shaft

at 20 rev/s?

A. 1.665 MW C. 6.155 MW

B. 3.665 MW D. 7.244 MW

ANSWER: 1.665 MWSOLUTION:

( )

( )

( )

( )( )

MW1.665

20213,252

shaftabydtransmittepower2T

m-N13,252T

104

100016T60

d

16TS

2

3s

=

=

=

=

=

=

28. What do you call the type of reaction in which heat is absorbed?

A. endothermic C. exothermic

B. redox rection D. isothermic

ANSWER: endothermic

29. The ratio between the energy dissipated in some process and the heat appear

as a result is the

A. specific heat C. kilocalorie

B. triple point D. mechanical equivalent of heat

ANSWER: mechanical equivalent of heat

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30. The light cable supports a mass of 12 kg per meter of horizontal length and

is suspended between the two points on the same level 300 m apart. If the sag is

60 m, find the length of the cable.

A. 329 m C. 139 m

B. 239 m D. 429 m

ANSWER: 329 mSOLUTION:

( )( )

( )

( )m329S

3005

6032

3003

608300S

5L

32d

3L

8dLS

3

42

3

42

=

++=

++=

31. The Golden Gate Bridge in San Francisco has a main span of 1280 m, a sag of

143 m, and a total static loading of 310.8 kN per linear meter of horizontal

measurement. The weight of both of the main cable is included in this load and i

assumed to be uniformly distributed along the horizontal. Calculate the midspan

tension in each of the main cables.

A. 233 MN C. 223 MN

B. 322 MN D. 232 MN

ANSWER: 23 MNSOLUTION:

( )( )( )

MN223H

MN4452H

1428

128010310.82H

cablestwofor8d

L2H

23

2

=

=

=

=

32. Two wires, A and B, are made of the same material and are subjected to the

same loads. The strain is greater for A when

A. has twice the diameter of B

B. A has twice as long as B

C. A has twice the length and half the diameter

D. A has twice the diameter and half the length

ANSWER: A has twice the length and half the diameter

33. Electron are emitted from a metal surface when light falling on it has a

minimum

A. energy C. wavelength

B. velocity D. change

ANSWER: energy

34. Who designed the atomic reactor?

A. Wilson C. Rutherford

B. Fermi D. Teller

ANSWER: Fermi

35. Whenever a system is made to complete a cyclic process, the workdone during

the complete cycle

A. is zero C. is negative

B. positive D. depends upon the path followed

ANSWER: depends upon the path followed

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36. Streamlined objects move more easily through fluids than those of irregular

shape. The reason is that

A. turbulence is decreased C. turbulence is increased

B. viscosity is increased D. viscosity is increased

ANSWER: turbulence is decreased

37. Two pieces of wire of the same material have their length in the ratio of 1

and diameters in the ratio of 2:1. If they are stretched by the equal force,

elongation will be in the ratio of

A. 1:2 C. 1:8B. 2:1 D. 8:1

ANSWER: 1:8

38. The volume strain for a constant applied force increases directly with an

increase in

A. volume C. surface area

B. compressibility D. bulk modulus

ANSWER: compressibility

39. Bernoullis equation includes as a special case

A. Hookes Law C. Newtons third law of motion

B. Toricellis theorem D. Archimedes principleANSWER: Toricellis theorem

40. In a city water system the water will flow

A. from the mains to the water outlet

B. only if the outlet is higher than the water in the water tower

C. faster from a first floor tap than from one on the third floor

D. only when the water tower has been completely emptiedANSWER: faster from a first floor tap than from one on the third floor

41. The nib of a pen is split keeping in view the phenomenon of

A. diffusion C. osmosis

B. capillarity D. cohesionANSWER: capillarity

42. A double convex air bubble in water acts as

A. converging lens C. diverging lens

B. pane slab D. none of these

ANSWER: diverging lens

43. What determines longitudinal chromatic aberration of a lens?

A. Dispersive power only C. Focal length only

B. Both dispersive power and focal length D. None of these

ANSWER: Both dispersive power and focal length

44. The energies of photo electrons in photoelectric effect

A. changes with intensity of light

B. changes with frequency of light

C. changes with velocity of light falling as the metal surface

D. None of the above is correct

ANSWER: changes with frequency of light

45. Which of the following functions is performed by a photocell?

A. It converts chemical energy into electrical energy

B. It converts magnetic energy into electrical energy

C. It converts light energy into electrical energy

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D. It converts electrical energy into light energy

ANSWER: It converts light energy into electrical energy

46. The maximum energy of emitted photoelectron is measured by

A. the largest potential difference they can traverse

B. the current they produce

C. the potential difference they produce

D. the speed with which they emerge

ANSWER: the speed with which they emerge

47. The theory that light is emitted in discrete amounts of energy rather than i

a continuous fashion is known as

A. the photoelectric effect

B. the quantum theory

C. Huygens principle

D. the electromagnetic theoryANSWER: the quantum theory

48. Which of the following colour phenomenon is not an interference phenomenon?

A. Oil spread on the surface of water exposed to extended sources of light

exhibits brilliant colours

B. Soap bubbles in sunlight show coloursC. Sky appears blue at noon but red in the evening and dawn

D. Metallic surface when heated show colours

ANSWER: Sky appears blue at noon but red in the evening and dawn

49. Air bubbles in water shines because of

A. reflection C. refraction

B. diffraction D. total internal reflectionANSWER: total internal reflection

50. When a helium atom loses an electron it becomes

A. an alpha particle C. a proton

B. a positive helium ion D. a negative helium ionANSWER: a positive helium ion

51. Emission of a -particle from a nucleus

A. changes its atomic number C. changes its mass number

B. changes both the above D. None of these

ANSWER: changes its mass number

52. Which of the following propagate at the same speed as velocity of light?

A. Heat waves C. Sound waves

B. Shock Waves D. -rays

ANSWER: Heat waves

53. The standard fixed point for calibrating a thermometer is

A. the boiling point of water C. the boiling point of ice

B. the temperature of steam D. the triple point of water

ANSWER: the triple point of water

54. The gas thermometer is taken as the primary standard because

A. the thermometers are easily reproducible

B. readings can be accurately taken

C. no corrections are necessary

D. it reproduces the thermodynamic scale

ANSWER: it reproduces the thermodynamic scale

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55. The Carnot Cycle is a

A. reversible cyclic process with two isotherms and two adiabatics

B. constant pressure cycle

C. constant-volume cycle

D. a reversible two-stroke cycle

ANSWER: reversible cyclic process with two isotherms and two adiabatics

56. The process by which nuclei emit ,and - rays in order to attain stabilit

is calledA. radioactive disintegration C. decay

B. radioactivity D. radioactive transmutation

ANSWER: radioactivity

57. The process by which a heavy nucleus splits up into two lighter nuclei is

known as

A. fission C. fusion

B. decay D. a chain reaction

ANSWER: fission

58. Which atomic particle is used to cause fission in an atomic reactor?

A. Alpha particle C. Beta particleC. Deuteron D. Neutron

ANSWER: Neutron

59. The driver of an automobile traveling at speed v suddenly sees a brick wal

at a distance d directly in front of him. To avoid crashing

A. it is better to turn the car sharply away from the wall

B. it is better to slam on the brakes

C. the choice depends on the height of the brick wall

D. it is difficult to decide

ANSWER: it is difficult to decide

60. A particle having rest mass equal to that of electron but charge equal andopposite to that of electron is called

A. proton C. positron

B. hyperon D. meson

ANSWER: positron

61. Which is the most massive particle?

A. Deutron C. particle

B. Neutron D. Positron

ANSWER: particle

62. Kelvins statement of the second law of thermodynamics is called the law of

Degeneration because

A. all the heat supplied to the working substance is converted into work

B. in heat engines, heat can be converted to mechanical energy

C. some of the heat supplied to the working of substance is not available

D. the heat engine is not very efficient

ANSWER: some of the heat supplied to the working of substance is not available

63: Thermodynamics is a subject dealing with

A.the motion of molecules in matterB.The macroscopic variables, such as pressure, temperature and volumeC.the motion of atoms in matterD.the kinetic energy of molecules

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ANSWER: The macroscopic variables, such as pressure, temperature and volume

64. Which of the following constitute particles?

A. Electrons C. Protons

B. Photons D. None of these

ANSWER: Electrons

65. Why does nuclear fission requires high temperature?

A. Because all nuclear reactions absorbs heat

B. The mass deficit must be suppliedC. The particles can not come together unless they move rapidly

D. The binding energy must be supplied from external sources

ANSWER: Because all nuclear reactions absorbs heat

66. Who discovered radioactivity?

A. M. Curie C. Bequerel

B. Both the above D. None of these

ANSWER: Bequerel

67. The source of energy of the sun

A. fusion of heavy nuclei C. fusion of light nuclei

C. fission of light nuclei D. All of the aboveANSWER: fusion of light nuclei

68. Which of the following phenomenon is responsible for the production of

shadow?

A. Interference C. Diffraction

B. Polarization D. Rectilinear propagation of light

ANSWER: Rectilinear propagation of light

69. The defect in image due to oblique centric rays falling on the lens is calle

A. astigmatism C. coma

B. curvature of image field D. spherical aberration

ANSWER: curvature of image field

70. The burring of the image due to dispersion in lens is called

A. spherical aberration C. chromatic aberration

B. astigmatism D. curvature of image field

ANSWER: Chromatic aberration

71. When a body is accelerated

A. its velocity always changes C. its direction always changes

B. its speed always changes D. its falls towards the earth

ANSWER: its velocity always changes

72. A 2000 kg truck traveling at 36km/hr strikes a tree and comes toa top in 0.1

sec. The average force on the truck during the crash is

A. 2x103newtons C. 2x102newtons

B. 2x104newtons D. 2x105newtons

ANSWER: 2x105newtons

73. When a charged particle moves through a magnetic field, it suffers a change

in its

A. charge C. energy

B. mass D. direction of motion

ANSWER: direction of motion

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74. Lenzs law follows from the law of conversion of

A. mass C. charge

B. energy D. momentum

ANSWER: mass

75. If a car is moving towards you with its horn sounding, you hear a higher

pitch than you would hear if the car were at rest, this is because

A. the waves travel faster

B. successive crests produced by the horn are closer to each other

C. you received successive crests more frequently even though the waveitself is unchanged

D. the motion of the car raises the frequency of the horn

ANSWER: you received successive crests more frequently even though the waveitself is unchanged

76. A tuning fork Aproduces 4 beats with a tuning fork Bof frequency 256. Ais

filled at the top of the prong and the number of beats increases. What was its

original frequency?

A. 260 C. 258

B. 252 D. 250

ANSWER: 260

77. Neutral temperature of a thermocouple is the temperature at which

A. the thermo e.m.f. changes sign

B. the thermo e.m.f. is maximum

C. the thermo e.m.f. is minimum

D. the thermo current is maximum

ANSWER: the thermo e.m.f. is maximum

78. Factor of safety may be defined by

A. yielding stress/yielding stress C. working stress/yielding stress

B. breaking stress/working stress D. all of the above

ANSWER: breaking stress/working stress

79. The first patented diode used as a detector for ratio signal is credited to

A. Edison C. de Forest

B. Fleming D. Thomson*

AMSWER: Thomson

80. A fathometer is an instrument used to measure

A. velocity of sound C. frequency of sound

B. depth of sea D. wavelength of sound

ANSWER: depth of sea

81. A satellite travels in a circular orbit at a speed of 20,000 km/h to stay a

a constant attitude. To escape from the earth, the speed would have to be

increased to

A. 28,000 km/h C. 21,000 km/h

B. 40,000 km/h D. 64,000 km/h

ANSWER: 40,000 km/h

82. When a car is traveling at constant speed around a circular track, a quantit

that is constant but not zero is

A. acceleration C. angular velocity

B. velocity D. angular acceleration

ANSWER: angular velocity

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84. Which element has the highest ionization energy?

A. Na C. Li

B. K D. Cs

ANSWER: Li

85. Kinetic energy of molecules is highest in

A. solids C. gases

B. liquids D. solutions

ANSWER: gases