An electric dipole is placed at the origin is directed along the x - axis . At a point P , far away from the dipole , the electric filed is parallel to y - axis . If OP makes an angle `theta ` with the x - axis then :

Options

A. `tan theta = sqrt(3)`
B. `tan theta = sqrt(2)`
C. `theta = 45^(@)`
D. `tan theta = 1/(sqrt(2))`

Answer

B

Explanation

`tan phi = 1/2 tan theta " " …(i)`
`phi = 90^(@) - theta `
`tan phi = tan (90^(@) - theta ) = cot theta " " …(ii)`

From eqn . (i)
`tan phi = 1/2 tan theta `
or `tan (90^(@) - theta) = 1/2 tan theta `
`cot theta = 1/2 tan theta `
or ` 1/(tan theta ) = 1/2 tan theta `
or `tan^(2) theta = 2 , or theta = sqrt(2)`