Answer only Question #1. See attached file for full problem description.
A thundercloud has the charge distribution as shown on the diagram. Treat this distribution as two point charges, a negative charge of -30 C at the height of 2 km above the ground and a positive charge of +30 C at the height of 3 km. The presence of these charges induces charges on the ground. Assuming the ground is a conductor, it can be shown that the induced charges can be treated as a charge of +30 C at the depth of 2 km below ground level and a charge of -30 C at the depth of 3 km. Consider point P1, which is just above the ground directly below the thundercloud, and point P2, which is 1 km horizontally away from P1.
a) Determine direction and magnitude of electric field at these points.
b) Letting zero of potential to be at infinity, determine the potential at these points
The solution shows how to calculate the electric field and the potential due to the charges of the thundercloud and the induced charge on the ground.