Question

An electric field of magnitude e is measured at a distance r from a point charge q. if the charge is doubled to 2q, and the electric field is now measured at a distance of 2r from the charge, what is the value of the new electric field?

Answer 1

Electric field is proportional to the charge and inversely proportional to the square of distance:

`E\propto(Q)/(r^(2))`
With charge 2q and distance 2r, the electric field is proportional to:

`E_(q)\propto(2q)/((2r)^(2))=(2q)/(4r^(2))=(1)/(2)(q)/(r^(2))`
The new electric field is half of that of the original measured field.