Topic : Heat

Questions 1 to 25: Select the best answer to each question. Note that a question and its answers may be split across a page break, so be sure that you have seen the entire question and all the answers before choosing an answer.

1. In a gasoline engine, the area in the cylinder head where the air-and-fuel mixture is burned is called the

A. intake valve.
B. piston.
C. combustion chamber.
D. cylinder.

2. If the absolute pressure of a gas is 550.280 kPa, its gage pressure is

A. 101.325 kPa.
B. 277.280 kPa.
C. 448.955 kPa.
D. 651.605 kPa.

3. The main difference between the internal combustion engine and the diesel engine is that the diesel engine

A. has no connecting rods.
B. does not utilize pistons.
C. does not have a crankshaft.
D. has no ignition system.

4. A temperature of 200°F is equivalent to approximately

A. 840°C.
B. 93.3°C.
C. 37.8°C.
D. 232°C.

5. The process in which a substance changes from a gaseous state to the liquid state is

A. condensation.
B. evaporation.
C. critical temperature.
D. absolute zero.

6. A silver bar 0.125 meter long is subjected to a temperature change from 200°C to 100°C. What will be the length of the bar after the temperature change?

A. 0.0000189 meter
B. 0.124764 meter
C. 0.00002363 meter
D. 0.00023635 meter

7. Which one of the following temperatures is equal to 5°C?

A. 41 K
B. 465 K
C. 278 K
D. 0 K

8. A quantity of a gas has an absolute pressure of 400 kPa and an absolute temperature of 110 degrees kelvin. When the temperature of the gas is raised to 235 degrees kelvin, what is the new pressure of the gas? (Assume that there's no change in volume.)

A. 510 kPa
B. 1.702 kPa
C. 854.46 kPa
D. 3.636 kPa

9. The density of water is the greatest at a temperature of

A. 273 K.
B. 4 K.
C. 277 K.
D. 0 K.

10. Which one of the following substances is a liquid fuel used in rocket engines?

A. Ammonia
B. Liquid oxygen
C. Potassium perchlorate
D. Codium nitrate

11. The transmission of heat requiring the movement of a liquid or a gas is

A. transduction.
B. radiation.
C. conduction.
D. convection.

12. The _______ is used to express absolute temperatures in the English system of measurement.

A. Kelvin scale
B. Fahrenheit scale
C. Rankine scale
D. Celsius scale

13. How much heat energy is required to raise the temperature of 5 kilograms of coal from 20°C to 220°C?

A. 4,187,000 J
B. 6,573 J
C. 1,314,718 J
D. 314 J

14. During the stage of internal combustion engine operation in which the piston rises and compresses the fuel in the combustion chamber,

A. the exhaust valve is open and the intake valve is closed.
B. the intake valve is open and the exhaust valve is closed.
C. both the intake and exhaust valves are closed.
D. both the intake and exhaust valves are open.

15. The amount of heat energy required to raise the temperature of a unit mass of a material one degree is

A. absolute zero.
B. a Btu.
C. its heat capacity.
D. a Joule.

16. Which of the following takes place in the combustion chamber of a gas turbine engine?

A. Fuel oil is stored with sufficient pressure.
B. A mixture of fuel oil and compressed air is ignited.
C. Fuel oil is mixed with a proper portion of compressed air.
D. Gases are cooled to a desired temperature.

17. Unlike other kinds of liquids, volatile liquids

A. ignite readily at a relatively low temperature.
B. flow rapidly at a relatively low temperature.
C. freeze readily at a relatively high temperature.
D. evaporate rapidly at a relatively low temperature.

18. A temperature of 273 K is the temperature at which water

A. lacks any moving molecules.
B. evaporates.
C. boils.
D. freezes.

19. The waste products of combustion leave the internal combustion engine through the

A. crankshaft.
B. cylinder.
C. intake valve.
D. exhaust valve.

20. Which of the following cools the air in a household refrigerator?

A. The transfer of heat from the air to the compressor due to expansion of the gaseous refrigerant
B. Reduction of the air temperature due to condensation of the gaseous refrigerant
C. Absorption of the heat from the air due to evaporation of the liquid refrigerant
D. The transfer of heat to the evaporator due to compression of the liquid refrigerant

21. What is the value of the temperature 15 degrees Celsius in degrees Kelvin?

A. 455 degrees
B. 258 degrees
C. 288 degrees
D. 475 degrees

22. How much heat is required to convert 0.3 kilogram of ice at 0°C to water at the same temperature?

A. 450,759 J
B. 100,375 J
C. 334,584 J
D. 167,292 J

23. What is the length of an aluminum rod at 65°C if its length at 15°C is 1.2 meters?

A. 1.201386 meters
B. 0.001386 meter
C. 1.214855 meters
D. 0.00180 meter

24. When the molecules in a body move with increased speed, it's possible that the body will change from a

A. liquid to a gas.
B. liquid to a solid.
C. gas to a solid.
D. gas to a liquid.

25. 20 cubic inches of a gas with an absolute pressure of 5 psi is compressed until its pressure reaches 10 psi. What is the new volume of the gas? (Assume that there's no change in temperature.)

A. 40 cubic inches
B. 100 cubic inches
C. 10 cubic inches
D. 5 cubic inches