Physics Practice Test

If you double the radiating surface area of a star, its power output increases by a factor of:

2

The maximum theoretical efficiency of an automobile engine based on the temperature difference between the burning fuel and the ambient air is:

70%

Which of the following liberates the most heat?

Condensing 1 gram of steam

The gulf stream is one of natures ways of transferring energy through:

Convection

The cooling of a house by an air conditioner lowers the entropy inside the house. Where does the entropy go?

Entropy is transferred to the air outside the house.

Why does the handle of a metal spoon submerged in boiling soup feel hot?

Heat from the soup is transferred through the spoon by conduction.

It is a hot summer day and your friend's apartment has no air conditioning. However, a brand new refrigerator lies unopened in the center of the living room. Being a creative person, your friend closes all the doors and windows of the apartment, unpacks the refrigerator, plugs it in, and turns it on. Your friend then opens the refrigerator door and uses a small fan to circulate the air past the refrigerator and throughout the room. After the refrigerator has operated for a few minutes, the average temperature in the room is:

Higher than it was before

The efficiency of a heat engine can be improved by

Increasing the difference in temperature between the cold and hot regions.

A shiny, white transparent surface prevents heat transfer because:

It has emissivity of zero and reflects all light that strikes it.

Having a compression ratio that is too high in a car engine can cause:

Knocking due to preignition of the fuel.

Which temperature scale has 273 as the boiling point of water?

No scale

During which stroke of the common four-stroke engine is useful work produced by the engine?

Power

People fighting forest fires carry emergency tents that have shiny aluminum outer surfaces. If there is trouble, a fire fighter can lie under the tent to block the heat from burning trees overhead. The tent helps because:

Radiation carries heat downward toward the fire fighter and the aluminum tent reflects most of that radiation.

Low-E coatings are placed on house windows because:

Radiative heat transfer is a big problem for clear windows but the Low E coating reflects the infrared light.

Moments before it is ignited by the spark plug, the mixture of fuel and air inside an automobile cylinder is compressed to very high density. During the compression process, the mixtures:

Temperature rises dramatically and so does its pressure.

The first law of thermodynamics states that:

The change in an object's internal energy is the difference between the heat added to the object and the work done by the object.

Opening a container of liquid in orbit above the earth would cause it to boil because:

The lack of an atmosphere means that there is no pressure thus lowering the boiling point.

heat pump is a device that:

Uses work to move thermal energy from a cold region to a warmer region.

Two objects in thermal equilibrium with a third object are in thermal equilibrium with each other. Which Law of Thermodynamics is this?

Zeroth