250+ TOP MCQs on Capacitance of a Multi Plate Capacitor and Answers

Basic Electrical Engineering Multiple Choice Questions on “Capacitance of a Multi Plate Capacitor”.

1. Which is the correct expression for capacitance of a multi plate capacitor?
A. C=absolute permittivity*A/d
B. C=Actual permittivity*(n-1)*A/d
C. C=Actual permittivity*(n)*A/d
D. Actual permittivity*(n+1)*A/d
Answer: B
Clarification: The correct expression is: C=Actual permittivity*(n-1)*A/d.
Where, n=number of plates, A=area of cross section of the plates, d=distance of separation between the plates.

2. What happens to the capacitance of a multi plate capacitor when the area of cross section of the plate decreases?
A. Increases
B. Decreases
C. Remains constant
D. Becomes zero
Answer: B
Clarification: When the area of cross section decreases, the capacitance also decreases since it is related by the formula C=Actual permittivity*(n-1)*A/d. Here, we can see that the capacitance is directly proportional to the area of cross section.

3. What happens to the capacitance of a multi plate capacitor when the distance of separation between the plate increases?
A. Increases
B. Decreases
C. Remains constant
D. Becomes zero
Answer: B
Clarification: When the distance of separation between the plates increases, the capacitance decreases since it is related by the formula C=Actual permittivity*(n-1)*A/d. Here, we can see that the capacitance is inversely proportional to the distance of separation.

4. What happens to the capacitance of a multi plate capacitor when the number of plates increases?
A. Increases
B. Decreases
C. Remains constant
D. Becomes zero
Answer: A
Clarification: When the number of capacitors increases, the capacitance also increases since it is related by the formula C=Actual permittivity*(n-1)*A/d. Here, we can see that the capacitance is directly proportional to the number of capacitors.

5. Find the capacitance of a multi plate capacitor whose actual permittivity= 5F/m, n=3, A=4m²and d=2m.
A. 10F
B. 20F
C. 30F
D. 40F
Answer: B
Clarification: The formula for capacitance of a multi plate capacitor: C=Actual permittivity*(n-1)*A/d.
Thus, C=5*(3-1)*4/2 = 20F.

6. Find the capacitance of a multi plate capacitor whose relative permittivity=5, n=3, A=4m² and d=2m.
A. 1.77*10^-10 F
B. 1.77*10¹⁰ F
C. 1.77*10^-11 F
D. 1.77*10¹¹ F
Answer: A
Clarification: The formula for capacitance of a multi plate capacitor: C=Relative permittivity*absolute permittivity*(n-1)*A/d.
C = 5*8.85*10^-12*(3-1)*4/2=1.77*10^-10.

7. Find the number of plates in the multi plate capacitor having C=20F absolute permittivity=5F/m, A=4m² and d=2m.
A. 1
B. 2
C. 3
D. 4
Answer: C
Clarification: The formula for capacitance of a multi plate capacitor: C=Actual permittivity*(n-1)*A/d.
Substituting the given values in the equation, we get n=3.

8. Calculate the distance between the plates of the capacitor having C=20F, actual permittivity = 5F/m n=3 and A=4m².
A. 1m
B. 2m
C. 3m
D. 4m
Answer: B
Clarification: The formula for capacitance of a multi plate capacitor: C=Actual permittivity*(n-1)*A/d.
Substituting the given values in the equation, we get d=2m.

9. Calculate the area of cross section of the multi plate capacitor having C=20F, actual permittivity=5F/m n=3 and d=2m.
A. 1m²
B. 2m²
C. 3m²
D. 4m²
Answer: D
Clarification: The formula for capacitance of a multi plate capacitor: C=Actual permittivity*(n-1)*A/d.
Substituting the given values in the equation, we get A=4m².

10. Calculate the number of plates in the multi plate capacitor having C=1.77*10^-10F relative permittivity=5, A=4m² and d=2m.
A. 1
B. 2
C. 3
D. 4