Quiz Physics Unit 9-12

A sample of gas is trapped in a rigid container. As the temperature of the gas is increased, the pressure increases. Which statement is not correct?

• The gas molecules have greater kinetic energy.

• The gas molecules hit the walls of the container harder.

• The gas molecules hit the walls of the container more frequently.

• The gas molecules move further apart.

What happens when the temperature of a liquid increases?

• The mass of the liquid increases, making the liquid less dense.

• The mass of the liquid increases, making the liquid more dense.

• The volume of the liquid increases, making the liquid less dense

• The volume of the liquid increases, making the liquid more dense.

A bar of metal, which is a good thermal conductor, is heated at one end. What is the main method of transfer of thermal energy along the bar?

• lattice vibration

• movement of atoms of the metal along the bar

• transfer by electrons

• vibration of atoms of the metal bar

A man puts some ice into a glass of water on a warm day. After a short time, he notices that the ice disappears and that water droplets appear on the outside of the glass.

Which two changes of state are taking place?

• condensation and freezing

• condensation and melting

• boiling and melting

• freezing and evaporation

An ice cube is placed in a beaker and is heated. The ice melts to form water, which evaporates at first and then boils. The steam condenses on a cold window in the room.

Which process involves a transfer of energy from the ice, water or steam to the surroundings?

• melting

• evaporating

• boiling

• condensing

A teacher shows his class a polystyrene cup. The polystyrene is a thick plastic with lots of tiny air bubbles in it. He asks the class why the cup is so good at keeping a hot drink warm.

Three suggestions are made:

1 It contains air which is a poor thermal conductor.

2 The air is trapped in tiny bubbles so very little convection is possible.

3 The plastic is a poor thermal conductor.

Which suggestions are correct?

• 1, 2 and 3

• 1 and 2 only

• 1 and 3 only

• 2 and 3 only

On a warm day, a carton of fresh milk is covered with a wet cloth.

Why does this help to reduce the temperature of the milk?

• Some water evaporates from the cloth so the remaining water becomes cooler.

• The water has a very high specific heat capacity.

• The water insulates the milk from the warm air around it.

• Water is always colder than the air around it.

Why can a gas be compressed easily into a smaller volume?

• The particles are far apart.

• The particles do not attract each other.

• The particles move randomly

• The volume of each particle can be reduced.

The water in a swimming pool exerts a pressure at the bottom of the pool. Which graph shows the relationship between the pressure exerted by the water and the depth of water in the pool? (Assume the density of water is constant.)

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The diagram shows the view of a room heated by a radiator. The arrowed line from X to Y is the path of the convection current in the air.

Which row about the air temperature and the air density at X and at Y is correct?

• A

• B

• C

• D