Chapter 6, Problem 20STP

To determine

To Describe: The generation of lightning between a cloud and the ground.

Explanation of Solution

Introduction:

The transfer of charge between two objects is due to an increase of static electricity.

When humid air rises to meet a colder layer of air, storm clouds can be formed. As air masses move and swirl in the cloud, convection current causes charge separation inside the cloud.

Negative charge accumulates at the bottom and positive charges at top of the cloud.

The negative charges at the cloud’s bottom repels the negative charges in the ground, tree, and house, inducing a positive charge on the ground below the cloud.

Cloud’s negative charges are attracted by the positive charges on the ground.

The cloud’s negative charges move towards the ground once the bottom of the cloud has accumulated sufficient negative charges. As the electric charges move through air, collision takes place between the atoms and the molecules. These collisions cause emission of light. Thus, storm clouds are generators of static electricity due to which static discharge occurs leading to lightning.

Conclusion:

Lightning occurs when negative charges at the bottom of the cloud are attracted by the positive charges on the ground.