Q7 of 16 Page 45

In places of hot climate, it is advised that the outer walls of houses be painted white. Explain.

In places of hot climate, it is advised that the outer walls of houses be painted white because white is a light color and more heat is reflected from the surface and there is less absorption of heat by the walls. It helps in keeping the house cool.


More from this chapter

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5

Discuss why wearing more layers of clothing during winter keeps us warmer than wearing just one thick piece of clothing?

 6

Look at Fig. 4.13. Mark where the heat is being transferred by

conduction, by convection and by radiation.


 8

One litre of water at 30°C is mixed with one litre of water at 50°C. The temperature of the mixture will be


a. 80°C


b. more than 50°C but less than 80°C


c. 20°C


d. between 30°C and 50°C

 9

An iron ball at 400C is dropped in a mug containing water at 400C. The heat will

a. flow from iron ball to water.


b. not flow from iron ball to water or from water to iron ball.


c. flow from water to iron ball.


d. increase the temperature of both.