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. 5 cm
B. `(25)/9 cm`
C. 10 cm
D. `4/13` cm

Answer

A

Explanation

Since, `E_p = 0`
`implies E_(p1) = E_(p2)`
`implies1/(4piepsilon_0) .(2p)/x^3 =1/(4pi epsilon_0).(2(64p))/((25-x)^3)`
`implies (25 -x)/x =4 implies 25 - x = 4x implies x = 5 cm`