Q. The radius of solid metallic non-conducting sphere is 60 cm and charge on the sphere is 500$\mu$C. The electric field at a distance 10cm from centre of sphere is
A) $2 \times 10^{6}NC^{- 1}$
B) $2 \times 10^{8}NC^{- 1}$
C) $5 \times 10^{6}NC^{- 1}$
D) $5 \times 10^{8}NC^{- 1}$
Explanation
(a) The point 10 cm from centre of sphere will be inside the sphere. Hence,
$E_{inside} = \frac{1}{4\pi\varepsilon_{0}}.\frac{qr}{R^{3}}$
Here,
$q = 500 \times 10^{- 6}C,\ r = 10cm = 0.1m,\ $
$R = 60\ cm = 0.60m$
$\therefore E_{inside} = \left( 9.0 \times 10^{9} \right) \times \frac{500 \times 10^{- 6} \times 0.1}{(0.60)^{3}}$
$= 2 \times 10^{6}NC^{- 1}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.