Discussion Forum

Two non conducting solid spheres of radii R and 2R, having uniform volume charge densities  $\rho_{1}$  and $\rho_{2}$ respectively, touch each other. The net electric field at a distance  2R from the centre of the smaller sphere, along the line joining the centre of the spheres, is zero. The ratio   $\frac{\rho_{1}}{\rho_{2}}$ CAN BE

Answer:

Explanation:

At point P

 If resultant electric field is zero then,

$\frac{KQ_{1}}{4R^{2}}=\frac{KQ_{2}}{8R^{3}}R$

 $\frac{\rho_{1}}{\rho_{2}}=4$

  At point Q

If resultant elecric field is zero  then

$\frac{KQ_{1}}{4R^{2}}+\frac{KQ_{2}}{25R^{2}}=0$
$\frac{\rho_{1}}{\rho_{2}}=-\frac{32}{25}(\rho_{1}$ must be negative )