THERMAL EXERCISE 4

Two rods of identical shape and size are left in a deep freezer overnight. One rod is made of plastic while the other is made of copper metal. Which of the two rods will feel colder to the touch?

An axle is too large to fit into the hole in a wheel that is made of the same material. How can the axle be made to fit into the hole?

• by cooling the axle alone

• by cooling the wheel alone

• by cooling both the axle and the wheel

• by heating both the axle and the wheel

A student has 3 sealed plastic bags. One bag is full of gas, one of liquid and one of solid. The student squeezes each bag to see if it changes shape, and heats each bag to see if it expands. Which bag contains gas?

• the one that changes shape easily and expands the least when heated

• the one that changes shape easily and expands the most when heated

• the one that is fixed in shape and expands the most when heated

• the one that is fixed in shape and expands the least when heated

The fillings for a hole in a tooth should be made from a material that

• expands more than the hole in the tooth

• expands by the same amount as the hole in the tooth

• expands less than the hole in the tooth

• does not expand when heated

The diagram below shows a temperature-controlled switch in a flashing Christmas tree bulb. Which property of matter is used to operate the switch?

• Conduction of electricity

• Conduction of thermal energy

• Radiation of heat

• Thermal expansion

A person finds it difficult to unscrew a metal lid from a bottle of jam. He then holds the bottle under hot water for some time and manage to unscrew the metal lid. Why is this?

• the air pressure in the bottle falls

• the glass expands more than the metal lid

• the metal lid expands more than the bottle

• the jam melts

A liquid is heated. Which statement is NOT correct?

• the molecules expand
• the molecules gain energy
• the molecules move further apart
• the molecules move faster

Solids,liquids and gases expand differently for the same temperature change. What is the order of magnitude of expansion of solids, liquids and gases?

• A
• B
• C
• D

The diagram below shows part of a railway line. Which process is catered for by the gaps in the rails?

The figure below shows a flask filled with a gas. A capillary tube with a plug of water is fitted to the flask. Which direction will the plug of water move when the flask is placed in ice?