Question

$64$ identical drops of mercury are charged simultaneously to the same potential of $10$ volt. Assuming the drops to be spherical, if all the charged drops are made to combine to form one large drop, then its potential will be

• A. 100 V
• B. 320 V
• C. 640 V
• D. 160 V

Answer 1

Answer: (D)

$V=\frac{(64q)}{4\pi {\epsilon }_{0}R}=\frac{64q}{4\pi {\epsilon }_0(4r)}$
$=16\left(\frac{q}{4\pi {\epsilon }_{0}r}\right)=16\times 10=160V$