Question

A point charge is surrounded by eight identical charges at a distance r as shown in figure. How much work is done by the force of electrostatic repulsion when the point charge at the centre is removed to infinity–

• A. Zero
• B. $\frac{8q^{2}}{4\pi\varepsilon_{0}r}$
• C. $\frac{8q}{4\pi\varepsilon_{0}r}$
• D. $\frac{64q^{2}}{4\pi\varepsilon_{0}r}$

Answer 1

Answer: (B)

$\frac{8q^{2}}{4\pi\varepsilon_{0}r}$

Answer 2

Work done = – DU = U_i – U_f

= $\frac { 8 \mathrm { kq } ^ { 2 } } { \mathrm { r } }$ – O

=