Multiple choice questions on capacitance with brief explanatory answers.

Contents

- 1 Which of following is relationship of capacitance of a capacitor to relative permittivity
- 2 A capacitor opposes against change in which of following electrical properties
- 3 It is desired to increase the capacitance of a parallel-plate capacitor. Which of following sheet should be introduced between the plates of the capacitor
- 4 What happens to p.d, if plates of a charged parallel -plate capacitor are pulled apart
- 5 Assuming the capacitance of earth to be a spherical conductor of radius 6400 km is
- 6 A leakage capacitor can be represented using a capacitance C and resistance R in parallel C
- 7 Capacitance grading of cable involves
- 8 If length of a cable is doubled, its capacitance
- 9 Which of following dielectric is used in capacitance grading of cables
- 10 Static capacitors are rated in

## Which of following is relationship of capacitance of a capacitor to relative permittivity

Which of following is relationship of capacitance of a capacitor to relative permittivity

- Capacitance is directly proportional relative permittivity
- Capacitance is inversely proportional
- Capacitance is directly proportional to cube of
- Capacitance is directly proportional to square of

Correct answer: 1. Capacitance is directly proportional relative permittivity

## A capacitor opposes against change in which of following electrical properties

A capacitor opposes against change in which of following electrical properties

- Change in current
- Change in voltage
- Both of these
- None of the above

Correct answer: 2. Change in voltage

## It is desired to increase the capacitance of a parallel-plate capacitor. Which of following sheet should be introduced between the plates of the capacitor

It is desired to increase the capacitance of a parallel-plate capacitor. Which of following sheet should be introduced between the plates of the capacitor

- Copper
- Stainless steel
- Mica
- Tin

Correct answer: 3. Mica

## What happens to p.d, if plates of a charged parallel -plate capacitor are pulled apart

What happens to p.d, if plates of a charged parallel -plate capacitor are pulled apart

- P.d. Will decrease
- P.d. Will increase
- P.d. Will remain unchanged
- None of above

Correct answer: 2. P.d. Will increase

## Assuming the capacitance of earth to be a spherical conductor of radius 6400 km is

Assuming the capacitance of earth to be a spherical conductor of radius 6400 km is

- 711 µF
- 644 µF
- 2000 µF
- 200 µF

Correct answer: 1. 711 µF

Derivation for above starts at 8:00 in below video:

## A leakage capacitor can be represented using a capacitance C and resistance R in parallel C

A leakage capacitor can be represented using a capacitance C and resistance R in parallel C:

- False
- True

Correct answer: 2. True

## Capacitance grading of cable involves

Capacitance grading of cable involves:

- Grading according to capacitance of cables per km length
- Cables using single dielectric in different concentrations
- Capacitance required to be introduced at different lengths to counter the effect of inductance
- Use of dielectrics of different permeability values

Correct answer: 4. Use of dielectrics of different permeability values

## If length of a cable is doubled, its capacitance

If length of a cable is doubled, its capacitance:

- Becomes double
- Becomes one-fourth
- Remains unchanged
- Becomes one-half

Correct answer: 1. Becomes double

## Which of following dielectric is used in capacitance grading of cables

- Which of following dielectric is used in capacitance grading of cables:

- Porous dielectric
- Composite dielectric
- Hygroscopic dielectric
- Homogeneous dielectric

Correct answer: 2. Composite dielectric

## Static capacitors are rated in

Static capacitors are rated in:

- Kwh
- Kw
- Kvar
- None of these

Correct answer: 3. Kvar

Bonus: