Physics

Problem

Charge is distributed within a sphere of radius

R

with a volume charge density

\rho(r) = \frac{A}{r^2} e^{-2r/a}

where

A

and

a

are constants. If

Q

is the total charge of this charge distribution, the radius

R

is: a.

a \log \left( 1 - \frac{Q}{2\pi a A} \right)

\frac{a}{2} \log \left( \frac{1}{1 - \frac{Q}{2\pi a A}} \right)

a \log \left( \frac{1}{1 - \frac{Q}{2\pi a A}} \right)

\frac{a}{2} \log \left( 1 - \frac{Q}{2\pi a A} \right)