9 Thermal Properties and Temperature 2023 [EUT]

A bimetallic strip is used to control the temperature of an electrical appliance. It is made of two different metals fixed together. The diagram shows the shape of the bimetallic strip before and after heating. Which statement is correct?

• Metal P contracts more than metal Q on heating.

• Metal Q contracts more than metal P on heating.

• Metal P expands more than metal Q on heating.

• Metal Q expands more than metal P on heating.

A wooden wheel can be strengthened by putting a tight circle of iron around it.

Which action would make it easier to fit the circle over the wood?

• cooling the iron circle only

• heating the iron circle

• heating the wooden wheel and cooling the iron circle

• heating the wooden wheel but not heating or cooling the iron circle

What happens when a metal block is heated?

• Its width, height and length all increase.

• Its width increases only.

• Its height increases only.

• Its length increases only.

Which statement about the temperature of the solid describes what happens when a solid is melting?

• The temperature increases and there is an input of energy.

• The temperature increases and there is no input of energy.

• The temperature remains constant and there is an input of energy.

• The temperature remains constant and there is no input of energy.

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.

A chef heats some water in a pan on a hotplate.

The temperature of the water rises by 10 °C in time t.

She then puts the same volume of oil in an identical pan on the same hotplate.

The specific heat capacity of water is 2.5 times that of oil and water is 1.1 times denser than oil.

What is the time for the temperature of the oil to rise by 10 °C?

• 0.36t

• 0.44t

• 2.3t

• 2.8t

Liquid evaporates from a beaker. What happens to the temperature of the remaining liquid and how does this temperature change affect the rate of evaporation?

• Temperature decreases, rate of evaporation decreases

• Temperature decreases, rate of evaporation increases

• Temperature increases, rate of evaporation decreases

• Temperature increases, rate of evaporation increases

Thermal energy ΔE is supplied to an object of mass m which does not change its state during the heating process. The temperature of the object rises by ΔT. What is the specific heat capacity of the object?

• ΔE/mΔT

• mΔT/ΔE

• ΔEΔT/m

• ΔEm/ΔT

A student splashes water on to her face. Here are three statements about the effects. P. The water uses energy to evaporate. Q. The water gains energy from the student. R. The face of the student cools. Which statements are correct?

• P and Q only

• P and R only

• Q and R only

• P, Q and R

Four containers each contain water. More water at the same temperature is added to each container. From which container does water now evaporate more slowly than it did before?

• A

• B

• C

• D