Available Answers

1. 1.

   Why do telephone wires sag in summer?

2. 2.

   Why does a plate become hot when hot food is placed on it?

3. 3.

   Why are blocks of ice wrapped in thick jute cloth when they are transported?

4. 4.

   Identify the mode of heat transfer in each case. Give reasons for your answer.

   1. A cool metal spoon becomes hot when it is placed in a cup of hot coffee.
   2. A smoke detector placed near the ceiling of a room beeps when there is a fire.
5. 5.

   Why do people living in hot places paint the outer walls of their houses white?

6. 6.

   Give one word or phrase for the following:

   1. The degree of hotness or coldness of an object.
   2. The thin inner tube of a thermometer that contains liquid.
   3. The transfer of heat in solids through the vibration of molecules.
   4. The breeze that blows from the sea to the land in the afternoon in coastal areas.
   5. Transfer of heat in the absence of a medium.