Worksheet Chapter 9: Heat

1. Describe how a bimetallic strip operates inside an electric iron thermostat when the iron reaches a set high temperature.

2. A thermos flask is designed to keep hot drinks warm for long periods. Identify how each feature minimizes heat loss: (a) Vacuum space between double glass walls, (b) Silvered inner glass surfaces, and (c) Stopper plug made of plastic or cork.

3. Fill in the blank: The transfer of heat energy through fluid motion involving density changes is known as ________.

4. True or False: Dark and dull surfaces are good reflectors of thermal radiation.

5. A student attempts to open a glass jar with a tight metal lid that refuses to budge. (a) Suggest a thermal method to loosen the metal lid easily. (b) Explain the scientific reason behind your method.

6. State TWO differences between heat and temperature.

7. Explain the formation of a land breeze during the night near coastal areas.

8. Which method of heat transfer enables thermal energy from the Sun to reach the surface of the Earth across empty space?

9. True or False: Gases expand more than liquids and solids when subjected to the same increase in temperature.

10. Define the term 'thermal equilibrium'. State what happens to heat energy transfer and temperature when a hot copper block is immersed in cold water inside an insulated container.