A spherical conductor of radius $12 ext{ cm}$ has a charge of $1.6 imes 10^{-7} ext{ C}$ distrib

Question

A spherical conductor of radius $12	ext{ cm}$ has a charge of $1.6 	imes 10^{-7}	ext{ C}$ distributed uniformly on its surface. What is the electric field just outside the sphere?

Professor PC Thomas Classes · Answer

Just outside the sphere, the field is equivalent to a point charge at the center: $E = \frac{1}{4\pi\epsilon_0}\frac{q}{R^2} = 9 	imes 10^9 	imes \frac{1.6 	imes 10^{-7}}{(0.12)^2} = \frac{14.4 	imes 10^2}{0.0144} = 10^5	ext{ N/C}$.