Question

The charge given to a hollow sphere of radius $10\, cm$ is $3.2 \times 10^{-19}$ coulomb. At a distance of $4\, cm$ from its centre, the electric potential will be

• A. $28.8 \times 10^{-9}$ volts
• B. 288 volts
• C. 2.88 volts
• D. zero

Answer 1

Answer: (A)

Potential is to be determined at a distance of $4\, cm$ from centre of sphere i.e., inside the sphere.
$V=\frac{k q}{r}=\frac{9 \times 10^{9} \times 3.2 \times 10^{-19}}{10 \times 10^{-2}}$
$=28.8 \times 10^{-9}$ volts