Quiz

QUIZ

1. What is the best physics definition of heat?

a. It is the internal energy of a system. b. It is the work done between two systems of different energy levels. c. It is the potential of the system to do work because of its internal energy. d. It is the spontaneous transfer of internal energy from one object to another.

Answer: d. Heat is not the same thing as temperature. It involves the spontaneous transfer of stored internal energy from one object to another, which is transferred because of differences in temperature.

2. What is the SI unit for heat?

a. Joule b. Degree c. Kilocalorie d. Calorie

Answer: a. Remember that heat is energy and, in all cases, SI units for energy are joules, regardless of the type of energy being talked about. Degrees have nothing to do with actual energy and both the calorie and kilocalorie are non-SI units for heat energy.

3. On what condition or situation is heat transfer least dependent upon?

a. Mass of the system b. Temperature change in the system c. Phase of the objects d. Potential energy of the system

Answer: d. The mass of the system, the phase of the objects, and the change in temperature of the system are highly linked to heat transfer; however, the potential energy of the system is not usually related to heat transfer.

4. What is the best definition of specific heat of a substance?

a. The mass of a substance that will raise its temperature by one degree

Celsius if one Joule of energy is applied to it. b. The joules of energy held in a gram of a substance. c. The amount of energy necessary to raise a kilogram of a substance by one degree Celsius. d. The number of kilograms of a substance that will transfer one degree of heat to a kilogram of water.

Answer: c. The specific heat depends on the substance and on its phase. It is the amount of energy necessary to raise a kilogram of a substance by one degree Celsius.

5. Which substance has the greatest specific heat?

a. Copper b. Iron c. Alcohol d. Water

Answer: d. Water has the highest specific gravity of almost any type of substance. Liquid water has double the specific heat when compared to ice.

6. What is true of the heat involved to change a phase?

a. Heat is necessary to both freeze and condense a substance. b. Heat is released to both freeze and condense a substance. c. Heat is released to freeze but is necessary to condense a substance. d. Heat is necessary to freeze but is released in condensing a substance.

Answer: b. Heat is released when freezing and condensing a substance. It is necessary to melt and vaporize a substance, depending on the latent heat of vaporization and on the heat of fusion.

7. What form of heat transfer occurs during forced heating from a furnace that heats a house?

a. Radiation b. Convection c. Conduction d. Evaporation

Answer: b. Convection heating involves the movement of warm air through ducts that heat a room or house. This is an example of the heat transfer method of convection.

8. What form of heat transfer occurs when the sun warms the planet earth?

a. Radiation b. Convection c. Conduction d. Condensation

Answer: a. This is a form of radiance or radiant heat, in which actual electromagnetic waves of energy cause a rise in temperature of whatever place the electromagnetic waves reach. This is radiation.

9. When looking at conduction and insulation, what is the R factor?

a. A measure of the degree to which a substance conducts heat. b. A measure that is based on the square area of the substance. c. A measure of the energy required to heat a substance through conduction. d. A measure of the insulating ability of a substance.

Answer: d. The R factor is a measure of the insulating ability of a substance so that the higher the R factor, the less the heat can conduct through it. The rate of conduction is inversely proportional to the R factor.

10. What type of heat transfer is involved in the weather?

a. Convection b. Conduction c. Radiation d. Evaporation

Answer: a. Heat transfer from the hot equators to the cold poles, along with the spin of the earth, involves convection and the large transfer of heat from one place to another via air currents.