Question

A charge Q is distributed over a line of length L. Another point charge q is placed at a distance r from the centre of the line distribution. Then the force experienced by q is-

• A. $\frac{qQ}{4\pi \in_{0}(r^{2} - L^{2})}$
• B. $\frac{qQ}{4\pi \in_{0}(r^{2} - (L/2)^{2})}$
• C. $\frac{qQ}{4\pi \in_{0}r^{2}}$
• D. $\frac{qQL}{4\pi \in_{0}r^{3}}$

Answer 1

Answer: (B)

$\frac{qQ}{4\pi \in_{0}(r^{2} - (L/2)^{2})}$

Answer 2

dF =

F = $\frac { \mathrm { KQq } } { \mathrm { L } }$ $\int _ { r - \frac { L } { 2 } } ^ { r + \frac { L } { 2 } } \frac { d x } { x ^ { 2 } }$ = –

=