Q.4 Sometimes, a crackling sound is heard while taking off a sweater during winters. Explain.

A crackling sound is heard while taking off a sweater during winters. This happens due to electrostatic forces.

When the sweater gets rubbed with our body, then due to friction our body loses some electrons to the sweater, thus making the sweater negatively charged and leaving the body to become positively charged.

Now attraction takes place between negatively charged sweater and positively charged body as a result of electrostatic forces.