A charged belt, 61 cm wide, travels at 43 m/s between a source of charge and a sphere. The belt carries charge into the sphere at a rate corresponding to 100 µA. Compute the surface charge density on the belt.

Surface charge density will be

Explanation:

We have given speed of the belt v = 43 m/sec

Width of the belt w = 61 cm

We know that charge is equal to Q = It, here Is current and t is time

And time is equal to , here L is distance and v is speed

Putting the value of t in charge equation

Surface charge density is equal to

We know that width is equal to

So

electric field is a function of 1/r^2

yes, the force per unit charge for a point charge is inverse square law.