Question

3. Why do woollen clothes keep us warmer in winters than cotton clothes?
4. Why are ventilators in houses provided at the top of walls?
5. How does heat from the sun reach us? At what speed does this transfer of heat take place?
6. What is the function of the polished curved surface at the back of the heating rod in a room heater?
D. LONG-ANSWER QUESTIONS: Answer these questions.
1. Explain how heat is conducted from the heated end of a rod to its cold end.
2. With an example of each, explain the uses of good and bad conductors of heat.
3. Describe the process of convection of heat,
4. Explain with the help of diagrams how sea and land breezes are set up.
5. Black objects absorb more heat than white or polished ones. Give two daily uses of this principle.
6. Black objects radiate more heat than white objects. Give two everyday uses of this principle.
7. Draw a neat labelled diagram of a thermos flask. How does it prevent transfer of heat by
conduction, convection or radiation?
8. Two test tubes full of water are heated-one from below and the other near the top. In which
case will the water heat up faster and why?
HOTS QUESTIONS: THINK AND ANSWER,
In water, heat travels up much faster than it travels down. Explain,
In places with hot dimate, it is advised that the outer walls of houses be painted white. Explain why,
Two objects at the same temperature-one bigger than the other--are placed in contact.
Will heat be transferred from one object to another? Explain.​

Answer 1

Answer:

1)woollen clothes keep us warmer in winter as there are gaps in between them which have air

the warm air inside is blocked by the air in the holes which make woollen clothes a preferable choice in winters