what is the electric field

Question

A point charge Q is far from all other charges. At a distance of 4 m from Q, the electric field is 40 N/C. What is the electric field at a distance of 8m from Q?

Answer 1

A point charge Q is far from all other charges. At a distance of 4 m from Q, the electric field is 40 N/C. What is the electric field at a distance of 8m from Q?

Electric field due to isolated charge is inversely proportional to square of distance

So in distance is doubled , electric field gets 1/4th

at distance of 8 m , electric filed is 40/4 = 10 N/C ( as 8 is double of 4)