Three uncharged conducting large plates are placed parallel to each other in a uniform electric field. Find

electric field at a point P in the region between the plates

Options

A. E towards right
B. E towards left
C. zero
D. can't be found

Answer

A

Explanation

Let charge densities are induced as shown.
Electric field at points A, B, C should be zero.
Let us take point A:
Electric field at A due to plates K and L will be zero, because net charge on these plates is zero. So for field at A to be zero.
Electric field at A due to plate J = applied field

`implies (sigma)/(epsilon_(0))=Eimpliessigma=epsilon_(0)E`
Similarly we can find for B and C.
Now electric field inside the plate is zero because net charge on each plate is zero. Hence, electric field at P is equal to applied electric field which is E towards right.