Question

A non-conducting sphere of radius a has a net charge $+q$ uniformly distributed throughout its volume. A spherical conducting shell having inner and outer, radii b and c and a net charge $-q$ is concentric with the sphere (see the figure). Read the following statements
(i) The electric field at a distance $r$ from the center of the sphere = $\frac{1}{4\pi \epsilon_o} \frac {qr}{a^3} for\, r < a$
(ii) The electric field at distance $r$ from the center of the sphere for $a < r < b = 0$
(iii) The electric field at distance $r$ from the center of the sphere for $b < r < c < = 0$
(iv) The charge on the inner surface of the hollow sphere = $−q$
(v) The charge on the outer surface of the hollow sphere = $+q$.

• A. (i) (ii) and (v)
• B. (i), (iii) and (iv)
• C. (ii), (iii) and (iv)
• D. (ii), (iii) and (v)

Answer 1

Answer: (D)

Radius $= a$
charge $=+ q$
(i) The electric field at distance $r$ from the centre of the sphere $\frac{1}{4 \pi \epsilon_{0}} \frac{ qr }{ a ^{3}}$
This is correct
(ii) The electric field at distance $r$ from the centre of the sphere for $q < r < b =0$
(v) The charge on the outer surface of the hollow sphere $=+q$
(ii) and (v) are correct.