PHY12 Review Items Exit Exam

8/12/2019 PHY12 Review Items Exit Exam

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EXIT EXAM REVIEW

PHY12

By: fmn 06/06/14


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THERMAL EXPANSION

Linear Expansion


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Area Expansion

Change L to A and to : = 2

Volume Expansion

Change L to V and to : = 3

Stress = - Y T

Force,F = -Y A

T

THERMAL STRESS


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2 Common Effects of Heat

1. Change in temperature

2. Change in Phase

Change in Temperature

m m

Where:

m = mass of the body

C = specific heat

t = change in temperature

HEAT AND HEAT MEASUREMENTS


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Change in Phase

Fixed Pointspoints at which a substance will have a

change its phase without a change intemperature.

Freezing Point/Melting Point

water


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Boiling Point/Steam Point

steam


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Units CGS MKS FPS

C Cal/g-c Kcal/kg-c BTU/slug-F

Note: CGS/MKS

Cice 0.5

Cwater 1.0

Csteam 0.48

Units and values of Specific Heat, C


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Values of

L

cgs mks fps

80 cal/g 80 kcal/kg 144 BTU/slug

540

cal/g

540

kcal/kg

972 BTU/slug

Values of Latent Heat


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Principle of calorimetry (Mixing Substances)

Hotter bodieswill give off heat

Colder bodieswill absorb heat

By conservation of heat energy

Heat lost by hotter body = heat gained by colder

bodies


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Mode of Heat transfer

Conduction

Convection

Radiation

MECHANISM OF HEAT TRANSFER

H = Q/t

= rate of heat flow ( J or cal/s


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WAVE MOTION

Wave Speed,

wavelength,

Velocity of Transverse Wave,

(for vibrating string)

n

L2

Lm

Tv

Frequency, f

LmT

Lnf2

(String)

T

dL

nf (Wire)


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Mathematical Description of a Wave

tkxAtxy cos, Sinusoidal wave moving in (+) x direction

SOUND WAVE

Speed of Sound in a Liquid,

Speed of Sound in a Solid Rod,

Speed of Sound in Air,

Bv

Yv

tsmV

tscmV

6.0/332

60/200,33


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Resonance in an Air Column

Closed at One End

Open at Both Ends

Doppler Effect

1 1, 3, 5,4

n

vf n n n

L

1 1, 2, 3,2

n

vn n n

L


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Electricity

Ohms Law,

Electric Power, P

Electrical Energy,E

V IRV

I R

E = P X T

(Watts,W)

(KWH)

Voltage,V (V)

Current,I (Ampere, A)Resistance,R (Ohm,)


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Kirchhoffs Laws1. Kirchhoffs Point (or Junction) Rule I in = I out

2. Kirchhoffs Loop (or circuit) Rule sIRsemf ''


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1. Complete the following statement: A temperature decrease of 30 C is

equal to a temperature decrease of

A) 30 F.

B) 30 K.

C) 17 F.D) 26 F.

2. An aluminum tank of volume 0.0300 m3is filled to the top with mercury

at 20.0 C. The tank is placed inside a chamber with an interior

temperature of 70.0 C. The coefficient of volume expansion for mercury

is 1.82 104/C; and the coefficient of linear expansion of aluminum is23.0 106/C. After the tank and its contents reach thermal equilibrium

with the interior of the chamber, how much mercury has spilled?

A) 2.52 105m3

B) 6.60 105m3

C) 1.69 104m3D) 1.92 104m3


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3. A 0.30-kg lead ball is heated to 90.0 C and dropped into an ideal

calorimeter containing 0.50 kg of water initially at 20.0 C. What is the

final equilibrium temperature of the lead ball? The specific heat capacity

of lead is 128 J/(kg C); and the specific heat of water is 4186 J/(kg

C).A) 84.8 C

B) 20.8 C

C) 21.3 C

D) 27.8 C

4. The ends of a cylindrical steel rod are maintained at two different

temperatures. The rod conducts heat from one end to the other at a rate

of 10 cal/s. At what rate would a steel rod twice as long and twice the

diameter conduct heat between the same two temperatures?

A) 5 cal/sB) 10 cal/s

C) 20 cal/s

D) 40 cal/s


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5. A periodic wave is produced on a stretched string. Which one of the

following properties is notrelated to the speed of the wave?

A) frequency

B) amplitude

C) wavelengthD) tension in the string

6. What is the distance to the nearest antinode from the fixed end of a

guitar string vibrating at its first harmonic?

A) lB) 2l

C) l/2

D) l/4

7. What is the wavelength of a wave with a speed of 9.0 m/s and a period of

0.33 s?

A) 0.33 m

B) 1.5 m

C) 3.0 m

D) 13 m


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The displacement of a vibrating string versus position along the string is

shown in the figure. The periodic waves have a speed of 10.0 cm/s. Aand

Bare two points on the string.

9. What is the amplitude of the wave?A) 2 mm

B) 4 mm

C) 8 mm

D) 12 mm

10. What is the wavelength of the wave?A) 3.0 cm

B) 6.0 cm

C) 9.0 cm

D) 12 cm


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Two point charges are held at the corners of a rectangle as shown in the

figure. The lengths of sides of the rectangle are 0.050 m and 0.150 m.

Assume that the electric potential is defined to be zero at infinity.

11. Determine the electric potential at corner A.

A) +6.0 10

4

VB) 2.4 105V

C) +4.6 105V

D) 7.8 105V

12. What is the potential difference, VBVA, between corners Aand B?

A) 8.4 105

VB) 7.8 105V

C) 7.2 105V

D) 6.0 105V


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13. Which one of the following circuits has the largest resistance?

A) a

B) b

C) c

D) dE) e


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14. A resistor dissipates 1.5 W when it is connected to a battery with a

potential difference of 12 V. What is the resistance of the resistor?

A) 220 W

B) 18 W

C) 8.0 W

D) 96 W

Three resistors are connected as shown in the figure. The potential

difference between points Aand Bis 26 V.

15. What is the equivalent resistance between the points Aand B?

A) 3.8 WB) 4.3 W

C) 5.1 W

D) 6.8 W


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16. How much current flows through the 3-resistor?

A) 2.0 A

B) 4.0 AC) 6.0 A

D) 8.7 A


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17. Three resistors and two batteries are connected as

shown in the circuit diagram. What is the magnitude of

the current through the 12-V battery?A) 0.82 A

B) 0.30 A

C) 0.67 A

D) 0.52 A


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18. A train is moving toward a stationary observer with a speed of 30

m/s. The whistle of the locomotive has a frequency of 500 Hz and

the speed of sound of 340 m/s. What is the frequency heard by theobserver.

A) 458 Hz C) 458 Hz

B) 548 Hz D) 495 Hz

19. It is found out that 100 kcal of heat is just sufficient in changing a

certain amount of ice at -20oC to steam at 130oC. Determine the

mass of the ice. Ans. m = 0.13 kg

20. One end of the insulated metal rod is maintained at 100oC, and

the other end is maintained at 0oC by an ice-water mixture. The

rod is 60 cm long and has cross-sectional area of 1.25 cm2. Theheat conducted by the rod melts 8.50 g of ice in 10 min.

A) Find the thermal conductivity kof the metal.

B) What is the temperature at a point 25 cm from the hotter end

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PHY12 Review Items Exit Exam