Question

Under typical atmospheric conditions, there is an electric field near the earth's surface, directed downward, with a magnitude of 100 V/m.

Part A If we say that the potential at the earth's surface is 0 V, what is the potential 1.5 kmabove the surface?

Answer 1

The potential difference between two point and in a electric field is given by the line integral given below

where is a small line element along the path of integration and is the angle between and . In our problem is because is downward and is upward. In our problem point is earth surface where potential is zero, so . Also in our problem is constant, so we can take it out of integral. So the potential at point is given by

where is the distance between point and .

In our problem and . So the potential at point , above the earth surface is given by

So, the potential above the earth surface is .