Question

Three charges, each $+q$, are placed a at the corners of an isosceles triangle $ABC$ of sides $BC$ and $AC$, $2a$. $D$ and $E$ are the mid points of $BC$ and $CA$. The work done in taking a charge $Q$ from $D$ to $E$ is

• A. $\frac {3 q Q}{ 4 \pi \varepsilon_0 a }$
• B. $\frac{ 3 q Q}{ 8 \pi \varepsilon_0 a }$
• C. $\frac{ q Q}{ 4 \pi \varepsilon_0 a }$
• D. zero

Answer 1

Answer: (D)

zero

Answer 2

$W _{ D \rightarrow E }= Q \left[ V _{ E }- V _{ D }\right]$
$\because V _{ E }= V _{ D } \Rightarrow W _{ D \rightarrow E }=0$