The number of electrons to be put on a spherical conductor of radius `0.1m` to produce an electric field of `0.036N//C` just above its surface is

Options

A. `2.7 xx10^5`
B. `2.6 xx10^5`
C. `2.5 xx10^5`
D. `2.4 xx10^5`

Answer

C

Explanation

`E=(Kq)/(r^2) =("Kne")/(r^2)`
`implies n = (Er^2)/(Ke) = (0.036 xx(0.1)^2)/(9 xx10^9 xx1.6 xx10^(-19)) = 2.5 xx10^5`