1. Which is the correct expression for the 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

The correct expression for capacitance of a multi plate capacitor 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 a cross-section of the plate decreases?

A. Increases
B. Decreases
C. Remains constant
D. Becomes zero

Answer: B

When the area of the cross-section decreases, the capacitance also decreases since it is related to the formula

C = Actual permittivity × (n-1) × A/d.

Here, we can see that the capacitance is directly proportional to the area of the 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

When the distance of separation between the plates increases, the capacitance decreases since it is related to 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

When the number of capacitors increases, the capacitance also increases since it is related to 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 = 4m^{2}and d = 2m.

A. 10F
B. 20F
C. 30F
D. 40F

Answer: B

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 = 4m^{2} and d = 2m.

A. 1.77 × 10^{-10} F
B. 1.77 × 10^{10} F
C. 1.77 × 10^{-11} F
D. 1.77 × 10^{11} F

Answer: A

The formula for capacitance of a multi plate capacitor