Thermal energy and Heat

When a drill is used to bore a hole in an object...

• no useful work is done

• no energy is lost due to friction

• the drill is 100 percent efficient

• friction causes the object to heat up

Why does liquid rise in a thermometer?

• convection

• thermal expansion

• condensation

• radiation

The best thermal insulators

• conduct heat well

• are gases

• are metals

• have free electrons

A blow dryer transfers thermal energy mainly by

• conduction

• convection

• radiation

• specific heat

Which statement is NOT true about radiation?

• All object radiate

• Hot objects radiate faster than cold objects

• Radiation only transfers energy in matter

• The sun's energy reaches Earth by radiation

Energy added to a system...

• does work or increases thermal energy

• cannot heat the environment

• is converted to radiation

• reduces the kinetic energy of the system

All engines operate at less than 100 percent efficiency because they

• absorb heat

• conduct heat

• burn gasoline

• emit heat

Which occurs just before ignition?

• intake stroke

• compression stroke

• exhaust stroke

• power stroke

Which of the following is a FALSE statement about a heat pump?

• It requires no work

• It moves heat from a cold to a hot area

• It uses a refrigerant

• Air conditioners are heat pumps