A point negative charge -Q is placed at a distance r from a dipole with dipole moment P in the xy plane as shown in fig. The x-component of force acting on the charge-Q is

Options

A. `-(PkQ)/(r ) cos theta hat(i)`
B. `(PkQ)/(r ) cos theta hat(i)`
C. `-(2PkQ)/(r ) cos theta hat(i)`
D. `(2 PkQ)/(r ) cos theta hat(i)`

Answer

C

Explanation

`E_(1)=(2kPcos theta)/(r^3)hat i`

`vecF_(x)=-QvecE_(1)=(-2kPQ)/(r^(3)) cos theta hat i`.