Three large identical conducting parallel plates carrying charge `+Q , -Q, and +2Q`, respectively, are placed as shown in figure. If `E_A, E_b, and E_C` refer to the magnitudes of the electric field at points A, B, and C, respectively. Then

Options

A. `E_A gt E_B gt E_C`
B. `E_A = E_B gt E_C`
C. `E_A = 0 and E_B gt E_C`
D. `E_A = 0 and E_B = E_C`

Answer

D

Explanation

d.
`E_(P) = 0` (since it is a point inside conductor)
or `K[(Q-q)/(2epsilon_0) - 1/(2epsilon_0) + q/(2epsilon_0) + (Q-q)/(2epsilon_0) - (Q+q)/(2epsilon_0) - (Q-q)/(2epsilon_0)]` = 0
or `q = 0`
Clearly `= E_A = 0`
`E_(B) = -(2KQ)/(2epsilon_0) - (KQ)/(epsilon_0)`
`E_(C) = (2KQ)/(2epsilon_0) = (KQ)/(epsilon_0)`
In magnitude, `E_(B) = E_(C)`