Question

3. Answer the following questions in brief.
a) Crackling sound is heard while taking off your sweater during winters. Why?
b) Differentiate between the focus and the epicentre of an earthquake​

Answer 1

Answer:

Here's the answer

Explanation:

A. Sweaters are made up of wool , which is a poor conductor of electricity. When we are wearing the sweater the wool is in contact with our body, there is friction as there is rubbing between the body and the wool. ... due to this force, we hear the crackling sound while taking off the sweater during winters.

B. The point inside the crust where the pressure is released is called the focus . The point on the Earth's surface above the focus is called the epicentre . Earthquake energy is released in seismic waves. ... The waves are felt most strongly at the epicentre, becoming less strong as they travel further away.