Question

A point positive charge of Q' unit is moved round another positive charge of Q unit on a circular path. If the radius of the circle is r, the work done on the charge Q' in making one complete revolution is:

• A. $\frac{Q}{4\pi {ϵ}_{0}r}$
• B. $\frac{Q{Q}^{\prime }}{4\pi {ϵ}_{0}r}$
• C. $\frac{Q^{\prime }}{4\pi {ϵ}_{0}r}$
• D. $0$

Answer 1

Answer: (D)

$0$

We know potential at distance $r=\frac{kQ}{r}$
Now voltage is constant as r is constant
We know work done $w=\Delta$v $\cdot \upsilon$
$\Rightarrow$ w=0 as $\Delta$v=0