## 1. SI Unit of capacitance is ?

2. Henry
3. Coulomb
4. Ampere

Memory: SI unit of capacitance is Farad, but practical unit is micro-farad.

## 2. The capacitance of a capacitor depends on ?

1. The area of the plates
2. The distance between the plates
3. The dielectric material between them
4. All of the above

Memory: As per the capacitance formula, C = ϵ*A/d.

## 3. Dimensional formula of capacitance is ?

1. M-1L-2T3I3
2. M-2L-1T2I2
3. M-1L-2T4I2
4. M-1L-3T-2I-2

Memory: As per the formula, F = kg-1m-2s4A2

## 4. The value of 1F in e.s.u is ?

1. 3 × 1011
2. 3 × 108
3. 9 × 1011
4. 1/3 × 10-10

Memory: No information is available.

## 5. Which of the following acts as an open circuit for D.C and short circuit for A.C ?

1. Inductor
2. Resistor
3. Capacitor
4. Diode

Memory: As we all know that, capacitive reactance of a capacitor depends on frequency.

Therefore, as per the formula Xc= 1/2πfc, when, frequency is zero (D.C), capacitive reactance is very high and acts as a open circuit.

And when frequency is greater than zero (A.C), capacitive reactance is low and acts as a short circuit.

## 6. What happens, if the plates of a charged capacitor are kept apart ?

1. Decreases the capacitance
2. Increases the capacitance
3. Decreases the potential difference
4. Increases the potential difference

Memory: No information is available.

## 7. Capacity of a parallel plates capacitor can be increased by ?

1. Increasing the distance between the plates
2. Decreasing the distance between the plates
3. Increasing the length of the plates
4. Decreasing the thickness of the plates

Memory: According to formula, C = ϵ*A/d.

Where,

• C = Capacitance
• ϵ = Permittivity of dielectric
• A = Area of plates
• d = Distance between the plates

## 8. The equivalent capacitance between A and B in the above figure is ?

1. 12 µF
2. 14 µF
3. 18 µF
4. 25 µF

Memory: As per the formula, (6*6*6/6+6+6)+2 = 14

## 9. In the above figure, the two capacitors are connected in ?

1. Series
2. Parallel
3. Series-parallel
4. None of the above

Memory: In the above figure, two capacitors are connected in parallel.

## 10. Four capacitors of value 3µF, 5µF, 7µF and 9µF are connected in parallel across a potential difference of 12V.

### Their equivalent capacitance will be ?

1. 20 µF
2. 12 µF
3. 6 µF
4. 24 µF

Memory: Parallel connection of capacitors are similar to series connection of resistors.

Therefore,

When capacitors are connected in parallel, the equivalent capacitance is the algebraic sum of their individual capacitance.

## 11. Capacitor stores which type of energy ?

1. Mechanical energy
2. Heat energy
3. Gravitational energy
4. Potential energy