Question

Two large thin conducting plates with a small gap in between are placed in a uniform electric field E (perpendicular to the plates). The area of each plate is A, and charges +Q and -Q are given to these plates as shown in Fig. If R, S, and T are three points in space, then the

• A. field at point R is E
• B. field at point S is E
• C. field at a point T is $(E+\frac{Q}{{\epsilon }_{0}A})$
• D. field at a point S is $(E+\frac{Q}{A{\epsilon }_0})$

Answer 1

Answer: (A), (D)

The correct options are
A field at point R is E
D field at a point S is $(E+\frac{Q}{A{\epsilon }_0})$

At R, $E_{net}=E+\frac{Q}{2A{\epsilon }_0}-\frac{Q}{2A{\epsilon }_0}=E$
At S, $E_{net}=E+\frac{Q}{2A{\epsilon }_0}+\frac{Q}{2A{\epsilon }_0}=E+\frac{Q}{A{\epsilon }_0}$
At T, $E_{net}=E+\frac{Q}{2A{\epsilon }_0}-\frac{Q}{2A{\epsilon }_0}=E$