Two large, thin metal plates are parallel and close to each other. On their inner faces, the plates have surface charge densities of opposite signs and of magnitude 17.0×10−22 C/m2. What is E: (a) in the outer region of the first plate, (b) in the outer region of the second plate, and (c) between the plates?
Answers
Answer:
ANSWER
The situation is represented in the following figure.
A and B are two parallel plates close to each other. Outer region of plate A is labelled as I, outer region of plate B is labelled as III, and the region between the plates, A and B, is labelled as II.
Charge density of plate A, σ=17.0×10
−22
C/m
2
Charge density of plate B, σ=−17.0×10
−22
C/m
2
Electric field in regions can be found with the help of Gauss Law. In the regions, I and III, electric field E is zero. This is because charge is not enclosed by the Gaussian surfaces of the plates.
Electric field E in region II is given by the relation,
E=
∈
0
σ
Where,
∈
0
= Permittivity of free space =8.854×10
−12
N
−1
C
2
m
−2
∴E=
8.854×10
−12
17.0×10
−22
=1.92×10
−10
N/C
Therefore, electric field between the plates is 1.92×10
−10
N/C.
Explanation: