Question

If a rectangular area is rotated in a uniform electric field from the position where the maximum electric flux goes through it to an orientation where only half the flux goes through it, what has been the angle of rotation? A) 45° B) 26.6° C) 90° D) 30° E

Answer 1

Answer:

D) 30°

Explanation:

This is in accordance to the Gauss Law which states that, the electric flux through any closed surface is equal to the total charge enclosed by the surface divided by the permittivity of free space.

Mathematically given as:

$\phi=E.A\ cos \theta=\frac{Q_{enc}}{\epsilon_0}$

where

θ = the angle between the electric field lines and area vector normal to the surface.

When the area vector has formed an angle of 60° then the plane is at 30° and we know cos 60° = 0.5