A spherical conductor of radius $12\; cm$ has a charge of $1.6 \times 10^{−7}\;C$ distributed uniformly on its surface. What is the electric field at a point 18 cm from the center of the sphere ?

Question

$\begin{array}{1 1} 4 \times 10^{4}NC^{-1} \\ 4.4 \times 10^{4}NC^{-1} \\ 0.4 \times 10^{4}NC^{-1}\\ 5 \times 10^{4}NC^{-1}\end{array}$