Question

The earth has a vertical electric field at the surface, pointing down, that averages 113 n/c. This field is maintained by various atmospheric processes, including lightning. What is the direction of the electric field at the surface of the earth?

1) Upwards
2) Downwards
3) Horizontal
4) Cannot be determined

Answer 1

The Earth's electric field at the surface points downwards due to the net negative charge of the Earth and the positive charge of the ionosphere.

Step-by-step explanation:

The direction of the electric field at the surface of the Earth is downwards.

This is because the Earth has a net negative charge, while the ionosphere, which is a layer of charged particles about 100 km above the surface, is positive. The Earth's negative charge and the ionosphere's positive charge create an electric field that points downwards towards the Earth.

The magnitude of this electric field is approximately 150 N/C, and it increases slightly as we get closer to the surface of the Earth.