Test 4

1. Temperature of a subtance is...

A. a measure of the average potential energy of the particles comprising the substance.
B. a measure of the total kinetic energy of the particles comprising the substance.
C. a measure of the average kinetic energy of the particles comprising the substance.
D. a measure of the amount of heat an object has.
E. a measure of the total potential energy of the particles comprising the substance

2. 364 °K is equal to

A. 174.468 °F
B. 139.249 °F
C. 228.038 °F
D. 262.859 °F
E. 195.8 °F

3. A thermometer is based on the change of volume with change in temperature of a fluid in a tube. The fluid rises to a level of 0.015 m when the temperature is 7.5 °C and to a level of 0.1 m when the temperature is 18 °C. Obtain the calibrating equation; that is a formula for the temperature ( T ) in terms of the fluid level ( L ).

A. T = 105.741 * L + 3.637
B. T = 164.665 * L + 6.404
C. T = 123.529 * L + 5.647
D. T = 123.529 * L + 6.404
E. T = 105.741 * L + 5.647

4. By how much should the temperature of an aluminum rod of length 5 m change if its length is to change by 1e-2 m. (Coeeficient of linear expansion for aluminum is 2.4e-5 ⁄ °C.)

A. 83.333 °C
B. 30.857 °C
C. 19.196 °C
D. 135.333 °C
E. 100.812 °C

5. Calculate the change in area of a circular plate of radius 0.01 m made of steel when its temperature changes by 170 °C. (Coefficient of linear expansion for steel is 1.1e-5 ⁄ °C)

A. 1.175e-6 m²
B. 1.659e-6 m²
C. 0.353e-6 m²
D. 1.342e-6 m²
E. 2.01e-6 m²

6. The combined gas law states that the volume of an ideal gas is

A. is directly proportional to its temperature if its pressure is kept constant.
B. directly proportional to its temperature and inversely proportional to its pressure.
C. directly proportional to its temperature and pressure
D. inversely proportional to its pressure and temperature
E. directly proportional to its pressure and inversely proportional to its temperature

7. A gas in a balloon has a volume of 6 L at a temperature of 30 °C. Calculate its volume when its temperature is changed to 85 °C at constant pressure.

A. 9.928 L
B. 4.998 L
C. 0.9 L
D. 5.845 L
E. 7.089 L

8. Calculate the pressure of 30 g of carbon mono-oxide ( CO ) gas that has a volume of 7 L at a temperature of 90 °C. (atomic masses of carbon and oxygen are 12 and 16 u respectively.)

A. 169.281 kPa
B. 325.478 kPa
C. 461.158 kPa
D. 799.623 kPa
E. 752.266 kPa

9. How many molecules are there in a sample of gas that occupies a volume 3 L at STP.

A. 1.03e23
B. 1.409e23
C. 0.456e23
D. 0.807e23
E. 1.305e23

10. A 100 g sample of di-atomic Chlorine ( Cl2 ) gas is at a temperature of 100 °C. Calculate the RMS (root mean square) speed of the molecules of the sample. (atomic mass of Chlorine i is 35 u. )

A. 364.255 m ⁄ s
B. 500.904 m ⁄ s
C. 647.809 m ⁄ s
D. 411.151 m ⁄ s
E. 155.169 m ⁄ s

11. Amount of heat energy supplied to a substance...

A. is inversely proportional to the temperature of the substance.
B. is inversely proportional to the mass of the substance for a given change in temperature.
C. is proportional to the temperature of the substance.
D. is inversely proportional to the change in temperature of the substance.
E. is proportional to the change in temperature of the substance.

12. A bullet of mass 0.055 kg was fired into an aluminum metal (specific heat capacity 900 J ⁄ kg ⁄ °C) of mass 5 kg with a speed of 500 m ⁄ s. If half of the kinetic energy of the bullet is transferred to the aluminum metal as heat energy, by how much would the temperature of the aluminum metal increase?

A. 0.859 °C
B. 0.764 °C
C. 1.22 °C
D. 1.099 °C
E. 0.997 °C

13. A 0.85 kg of aluminum metal (specific heat capacity 900 J ⁄ kg ⁄ °C) at a temperature of 115 °C is mixed with 9 kg of water (specific heat capacity 4180 J ⁄ kg ⁄ °C) at a temperature of 22 °C. Calculate the equilibrium temperature of the mixture.

A. 44.775 °C
B. 2.806 °C
C. 23.853 °C
D. 31.301 °C
E. 35.808 °C

14. Calculate the amount of water (Latent heat of vaporization 2.26e6 J ⁄ kg) that can be vaporized by 5e6 J of heat energy.

A. 3.528 kg
B. 0.324 kg
C. 1.604 kg
D. 2.212 kg
E. 4.029 kg

15. Calculate the amount of heat energy required to change 0.691 kg of ice at a temperature of -10 °C to water at a temperature of 50 °C. (specific heat capacities of ice, water and steam are 2090, 4180, 2010 J ⁄ kg ⁄ °C respectively. Latent heat of fusion and vaporization of water are 3.34e5, 2.26e6 J ⁄ kg respectively.)

A. 389654.9 J
B. 574171.481 J
C. 691580.064 J
D. 140964.8 J
E. 189538.981 J

16. Which of the following is not a correct statement?

A. The rate of absorption of radiation by an object is proportional to the fourth power of its temperature.
B. The rate of emission of radiation by an object is proportional to the fourth power of its temperature.
C. The rate of emission of radiation by an object is proportional to the surface area of the object
D. The rate of absorption of radiation by an object is proportional to the surface area of the object.
E. The net rate of emission of radiation is equal to the difference between the emission and the absorption rate.

17. A rod made of copper (thermal conductivity 397 J ⁄ s ⁄ m ⁄ °C) has a length of 2 m and a cross-sectional radius of 0.02 m. Its left end and right end are at temperatures of 34 °C and 110 °C respectively. Calculate the amount of energy transferred from the left end to the right end in 60 minutes.

A. 117834.879 J
B. 12005.96 J
C. 88227.974 J
D. 60322.968 J
E. 68247.456 J

18. An spherical object of radius 0.1 m and emissivity 0.2 is at a temperature of 80 °C. Its enviornment is at a temperature of 10 °C. Calculate the amount of radiation energy emitted by the object in 2 s.

A. 44.488 J
B. 13.241 J
C. 63.195 J
D. 5.678 J
E. 80.745 J

19. An spherical object of radius 0.4 m and emissivity 0.9 is at a temperature of 85 °C. Its enviornment is at a temperature of 37 °C. Calculate the net rate of emission of radiation of the object.

A. 951.527 W
B. 741.694 W
C. 400.841 W
D. 866.164 W
E. 1074.447 W

20. Two systems are said to be in thermodynamic equilibrium if

A. they have the same pressure.
B. if they have the same kinetic energy.
C. they have the same temperature.
D. if they are at rest
E. they have the same energy.

21. The internal energy of a system of gas decreased by 600 J while being supplied with 850 J of heat energy. Calculate the work done by (on) the system.

A. 250 J
B. 1450 J
C. 0 J
D. -1450 J
E. -250 J

22. The volume of a system of gas decreased from 55 L to 10 L under a pressure of 80 kPa while being supplied with 300 J of heat energy. Calculate the change in its internal energy.

A. 3900 J
B. 3300 J
C. -3900 J
D. 0
E. -3300 J

23. The following is a PV dagram for a certain system of gas.

Calculate the heat supplied (lost) in taking the system from the point C( 6 L, 4 kPa) where its internal energy is 40 J to the point A( 2 L, 2 kPa), where its internal energy is 5 J, along path CDA.

24. The following is a PV dagram for a certain system of gas.

Calculate the heat supplied to (lost by) the system for the cyclic process ABCDA.

25. Which of the following statements is not a correct statement.

A. The gas state has more entropy than the liquid state.
B. An isolated system can only proceed from order to disorder.
C. The entropy of the universe can only increase.
D. The efficiency of a heat engine can be as high as a 100%.
E. The entropy of an isolated system can only increase.

26. A heat engine absorbs 1977 J of energy from a hot reservior at a temperature of 390 °C and gives off 791 J of energy to a cold reservior at a temperature of 30 °C in a cyclic process. Calculate the efficiency of the engine.

A. 52.342%
B. 59.99%
C. 94.529%
D. 44.165%
E. 104.012%

27. Calculate the change in entropy during the melting of 0.5 kg of ice.(Latent heat of fusion for water is 3.34e5 J ⁄ kg).

A. 611.722 J ⁄ °K
B. 1139.805 J ⁄ °K
C. 906.768 J ⁄ °K
D. 711.757 J ⁄ °K
E. 465.012 J ⁄ °K

Test 4: