Two electric dipoles of moment `P` and `64P` are placed in opposite direction on a line at a distance of `25 cm`. The electric field will be zero at point between the dipoles whose distance from the dipole of moment `P` is

Options

A. 10 cm
B. 5 cm
C. 8 cm
D. 20 cm

Answer

B

Explanation

Let us consider a neutral point O lies at a distance x from the dipole of moment p or at a distance `(25-x)` from dipole of 64 p.

At O, EF due to dipole `(1)=EF` due to dipole (2) `rArr" "(1)/(4pi epsilon_(0))(2p)/(x^(3))=(1)/(4pi epsilon_(0))(2(64p))/((25-x)^(3))`
`rArr" "(1)/(x^(3))=(64)/((25-x)^(3)) rArr x= 5 cm`