What is the electric field at the centre of a hollow conducting sphere of radius $R$ carrying total charge $Q$?
- $0$
- $\dfrac{kQ}{R^2}$
- $\dfrac{kQ}{R^3}$
- $\dfrac{kQ}{R}$
Show answer and solution
Correct answer: A. $0$
Inside any closed conducting shell with all charge residing on its outer surface, Gauss's law applied to a sphere of radius $r < R$ encloses zero charge
so $E = 0$ everywhere inside the cavity.