38 + Interview Questions in CAPACITANCE-AND-CAPACITOR IN GENERAL AWARENESS Page 1 InterviewSolution

1.	n small drops of the same size of the same size are charged to V volt each. They coalesce to form a big drop. The potential of the big drop will beA. `n^(1/3)V`B. `n^(2/3)V`C. `n^(3/2)V`D. `n^(3)V`
Answer» Correct Answer - B

Discussion

2.	When two charged conductors are joined by a thin conducting wire, charge flows from one to the orhter, untilA. Charges on them become equalB. their capacitances become equalC. their potentials become equalD. energy stored in them becomes equal
Answer» Correct Answer - C

Discussion

3.	A few capacitors are equally charged. Which of the figures shows the nature of variation of the potential difference V between their plates with their capacitances C?A. B. C. D.
Answer» Correct Answer - D

Discussion

4.	Two conducting spheres of radii `r_1" and "r_2` are connected by a thin conducting wire.Some amount of charges is given to the system. The charge will be shared between them in such a way that the ratio between the surface densities of charge on the spheres is equal toA. `(r_1)/(r_2)`B. `(r_2)/(r_1)`C. `(r_1^2)/(r_2^2)`D. `(r_2^2)/(r_1^2)`
Answer» Correct Answer - B

Discussion

5.	When a capacitor is connected to a dc battery,A. no current flows through the circuitB. current flows through the circuit for sometime, but eventually stopsC. current grows up and reaches a maximum value when the capacitor is fully chargedD. current reverses its direction alternately due to charging and discharging of the capacitor
Answer» Correct Answer - B

Discussion

6.	Two capacitors of capacitance `C_1" and "C_2` are connected in parallel. If a charge q is given to the assembly, the charge gets shared. The ratio of the charge on the capacitor `C_1` to the charge on `C_2` isA. `(C_1)/(C_2)`B. `(C_2)/(C_1)`C. `C_1C_2`D. `(1)/(C_1C_2)`
Answer» Correct Answer - A

Discussion

7.	A capacitor of capacitance `C_1` is charged up to potential V and then connected in parallel to an uncharged capacitor or capacitance `C_2`. The final potential difference across each capacitor will beA. `(C_2V)/(C_1+C_2)`B. `(C_1V)/(C_1+C_2)`C. `(1+(C_2)/(C_1))V`D. `(1-(C_2)/(C_1))V`
Answer» Correct Answer - B

Discussion

8.	A capacitor `C_1` of capacitance `5muF` is charged to a potetntial of 100V and another capacitor `C_2` of capacitance `8muF` is charged to 50V. The positive and negative plates are mutually connected. Amount of charge of the capacitor `C_2` after combination will beA. `4500muC`B. `7200muC`C. `(4500)/(13)muC`D. `(7200)/(13) muC`
Answer» Correct Answer - D

Discussion

9.	A capacitor `C_1` of capacitance `5muF` is charged to a potetntial of 100V and another capacitor `C_2` of capacitance `8muF` is charged to 50V. The positive and negative plates are mutually connected. Amount of charge of the capacitor `C_1` after combination will beA. `(4500)/(13) muC`B. `(7200)/(13) muC`C. `(2700)/(13) muC`D. `(11700)/(3) muC`
Answer» Correct Answer - A

Discussion

10.	A capacitor `C_1` of capacitance `5muF` is charged to a potetntial of 100V and another capacitor `C_2` of capacitance `8muF` is charged to 50V. The positive and negative plates are mutually connected. The final potential of the combination of the two capacitance will beA. `(500)/(3)V`B. `(900)/(13)V`C. `150 V`D. `50 V`
Answer» Correct Answer - B

Discussion

11.	A capacitor `C_1` of capacitance `5muF` is charged to a potetntial of 100V and another capacitor `C_2` of capacitance `8muF` is charged to 50V. The positive and negative plates are mutually connected. Energy loss will beA. `3.11xx10^(-13)J`B. `35xx10^(-2)J`C. `3.9xx10^(-13)J`D. `7.8xx10^(-5)J`
Answer» Correct Answer - C

Discussion

12.	A spherical drop of water carries a charge of `10xx10^(-12) C` and his a potential of 100V at its surface. Radius of the drop will beA. `9xx10^(-3)m`B. `9xx10^(-5)m`C. `9xx10^(-2)m`D. `9xx10^(-4)m`
Answer» Correct Answer - D

Discussion

13.	A parallel plate capacitor of plate area `0.2 m^2` and spacing `10^(-2)` is charged to `10^(3)V` and is then disconnected from the battery. If the plates are pulled apart to double the plates spacing capacitance of the capacitor will beA. `44.25 pF`B. `88.5 pF`C. `120.45 pF`D. `22.12 pF`
Answer» Correct Answer - B

Discussion

14.	A parallel plate capacitor of plate area `0.2 m^2` and spacing `10^(-2)` is charged to `10^(3)V` and is then disconnected from the battery. If the plates are pulled apart to double the plates spacing Final voltage of the capacitor will beA. `10^(3)V`B. `4xx10^(3)V`C. `2xx10^(3) V`D. `10^(6)V`
Answer» Correct Answer - C

Discussion

15.	Two capacitors `C_1 " and "C_2 (=2C_1)` are connected in a circuit with a switch. Initially, the switch is open and `C_1` holds charge Q. The switch is closed. At steady state, the charge on each capacitor would be A. `Q,2Q`B. `(Q)/(3),(2Q)/(3)`C. `(3Q)/(2),3Q`D. `(2Q)/(3),(4Q)/(3)`
Answer» Correct Answer - B

Discussion

16.	A parallel plate capacitor of plate area `0.2 m^2` and spacing `10^(-2)` is charged to `10^(3)V` and is then disconnected from the battery. Amount of work required to double the plate spacing isA. `8.85xx10^(-5)J`B. `17.7xx10^(-5)J`C. `4.42xx10^(-5)J`D. `26.55xx10^(-7)J`
Answer» Correct Answer - A

Discussion

17.	An electric bulb, a capacitor, a battery and a switch are all in series in a circuit. How does the intensity of light vary when the switch is turned on?A. Continuoes to increase graduallyB. Gradually increases for some time and then becomes steadyC. Sharply rises initially and then gradually decreasesD. Gradually increases for some time and then gradually decreases
Answer» Correct Answer - C

Discussion

18.	A capacitor of `4muF` connected as shown in the circuit. The internal resistance of the battery is `0.5 Omega`. The amount of charge on the capacitor plates will be
Answer» Correct Answer - D

Discussion

19.	An `1muF` capacitor C is connected to a battery of 10V through a resistance `1M Omega`. The voltage across C after 1 second is approximatelyA. `56 V`B. `7.8V`C. `6.3V`D. `10V`
Answer» Correct Answer - C

Discussion

20.	A combination is formed by connecting alternately n number of equidistant parallel pltes. If C be the capacitance for any two consecutive plates, then the capacitance of the whose system will beA. `C`B. `nC`C. `(n-1)C`D. `(n+1)C`
Answer» Correct Answer - C

Discussion

21.	A solid spere and a hollow sphere of the same diameter are charged to the same potential. ThenA. The charge on the hollow sphere will be greaterB. Both the spheres will have the same chargeC. only the hollow sphere will be chargedD. the solid sphere will have a greater amount of charge
Answer» Correct Answer - B

Discussion

22.	Five capacitors, each of capacitances C, are connected as in fig. 4.65. The ratio of the capacitance between P and R to that between P and Q is A. `3 : 1`B. `5 : 2`C. `2 : 3`D. `1 : 1`
Answer» Correct Answer - C

Discussion

23.	Find the equivalent capacitance between A and B. A. `5 muF`B. `4 muF`C. `3muF`D. `2 muF`
Answer» Correct Answer - A

Discussion

24.	There are six capacitors in the given network. Capacitance of each is `4 muF`. Effective capacitance between A and B is A. `24 muF`B. `12 muF`C. `(3)/(2)muF`D. `(2)/(3)muF`
Answer» Correct Answer - A

Discussion

25.	The capacity of a parallel plate capacitor is proportional to power n of the distance between the plates. The value of n isA. 1B. 2C. `-1`D. `-2`
Answer» Correct Answer - C

Discussion

26.	A parallel plate capacitor is connected to a battery. The plates are pulled apart with a uniform speed. If x is the separation between the plates, the time rate of change of electrostatic energy of capacitor is proportional toA. `x^(-2)`B. `x`C. `x^(-1)`D. `x^2`
Answer» Correct Answer - A

Discussion

27.	The capacitance of a parallel plate capacitor depends onA. the thickness of the platesB. the charge accumulated on the platesC. the potential difference between the two platesD. the distance between the two plates
Answer» Correct Answer - D

Discussion

28.	A parallel plate capacitor is charged and then disconnected from the charging battery. If the plates are now moved farther apart by pulling at them by means of insulating handles, thenA. the energy stored in the capacitor decreasesB. the capacitance of the capacitor increasesC. the charge in the capacitor decreasesD. the voltage across the capacitor increases
Answer» Correct Answer - D

Discussion

29.	A parallel plate capacitor is charged and the charging battery is disconnected. If the plates of the capacitor are moved further apart by means of insulating handles. ThenA. the charge on the capacitor increasesB. the voltage across the plates increasesC. the capacitance of the capacitor increasesD. the electrostatic energy stored in the capacitor increases
Answer» Correct Answer - B::D

Discussion

30.	The separation between the two plates of a parallel plate capacitor is d. A metal plate of equal area and of thickness `(d)/(2)` is inserted between the two plates. The ratio of the capacitances after and before this insertion isA. `2 : 1`B. `sqrt(2) : 1`C. `1 : sqrt(2)`D. `1 : 2`
Answer» Correct Answer - A

Discussion

31.	Statement I: Dielectric has no significance in a parallel plate capacitor. Statement II: Dielectric is an insulator which can be easily polarised on the application of electric field.A. Statement I is true, statement II is ture, statement II is a correct explanation for statement I.B. Statement I is true, statement II is ture, statement II is not a correct explanation for statement I.C. Statement I is true, statement II is false.D. Statement I is false, statement II is true.
Answer» Correct Answer - D

Discussion

32.	The electrostatic force between the metal plates of an isotated parallel plate capacitor C having a charge Q and area A, isA. proportional to the square root of the distance between the platesB. linearly proportional to the distance between the platesC. independent of the distance between the platesD. inversely proportional to the distance between the plates
Answer» Correct Answer - C

Discussion

33.	A dielectric slab of thickness d is inserted in a parallel plate capacitor whose negetive plate is at x=0 and positive plate is at x=3d. The slab is equidistant from the plates. The capacitor is given some charge by connecting it to a batterey. As x goes from 0 to 3d,A. the magnitude of electric field remains the sameB. the direction of electric field remains the sameC. the electric potential increases continuouslyD. the electric potential increases at first, then decreases and again increases
Answer» Correct Answer - B::C

Discussion

34.	A parallel plate capacitor is to be designed, using a dielectric of dielectric constant 5, so as to have a dielectric strength of `10^(9)V*m^(-1)`. If the voltage rating of the capacitor is 12kV, the minimum area of each plate required to have a capacitance of 80pF isA. `10.5xx10^(-6)m^2`B. `21.7xx10^(-6)m^2`C. `25.0xx10^(-5)m^2`D. `12.5xx10^(-5)m^2`
Answer» Correct Answer - B

Discussion

35.	A parallel plate air capacitor of capacitance C is connected to a cell of emf V and then disconnected from it. A dielectric slab of dielectric constant k, which can just fill the air gap of the capacitor, is now inserted in it. Which of the following is incorrect?A. the potential difference between the plates decreases k timesB. the energy stored in the capacitor decreases k timesC. the change in energy stored is `(1)/(2)CV^2((1)/(k)-1)`D. the charge on the capacitor is not conserved
Answer» Correct Answer - D

Discussion

36.	A parallel plate capacitor with oil(K=2) has a capacitance C. If the oil is removed, then the capacity of the capacitor becomesA. `sqrt(2)C`B. `2C`C. `(C )/(sqrt(2))`D. `(C )/(2)`
Answer» Correct Answer - D

Discussion

37.	Statement I: The capacity of a conductor, under given circumstances, remains constant irrespective of the charge present on it. Statement II: Capacity depends on size and shape of conductor and also on the surrounding medium.A. Statement I is true, statement II is ture, statement II is a correct explanation for statement I.B. Statement I is true, statement II is ture, statement II is not a correct explanation for statement I.C. Statement I is true, statement II is false.D. Statement I is false, statement II is true.
Answer» Correct Answer - A

Discussion

38.	A number of condensers of equal capacity C are arranged in n columns as shown in fig. The equivalent capacity is given by A. `nC`B. `n(n+1)C`C. `(n(n+1))/(2)C`D. `2n(n+1)C`
Answer» Correct Answer - C

Discussion

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n small drops of the same size of the same size are charged to V volt each. They coalesce to form a big drop. The potential of the big drop will beA. `n^(1/3)V`B. `n^(2/3)V`C. `n^(3/2)V`D. `n^(3)V`

When two charged conductors are joined by a thin conducting wire, charge flows from one to the orhter, untilA. Charges on them become equalB. their capacitances become equalC. their potentials become equalD. energy stored in them becomes equal

A few capacitors are equally charged. Which of the figures shows the nature of variation of the potential difference V between their plates with their capacitances C?A. B. C. D.

Two capacitors of capacitance `C_1" and "C_2` are connected in parallel. If a charge q is given to the assembly, the charge gets shared. The ratio of the charge on the capacitor `C_1` to the charge on `C_2` isA. `(C_1)/(C_2)`B. `(C_2)/(C_1)`C. `C_1C_2`D. `(1)/(C_1C_2)`

A capacitor of capacitance `C_1` is charged up to potential V and then connected in parallel to an uncharged capacitor or capacitance `C_2`. The final potential difference across each capacitor will beA. `(C_2V)/(C_1+C_2)`B. `(C_1V)/(C_1+C_2)`C. `(1+(C_2)/(C_1))V`D. `(1-(C_2)/(C_1))V`

A capacitor `C_1` of capacitance `5muF` is charged to a potetntial of 100V and another capacitor `C_2` of capacitance `8muF` is charged to 50V. The positive and negative plates are mutually connected. Energy loss will beA. `3.11xx10^(-13)J`B. `35xx10^(-2)J`C. `3.9xx10^(-13)J`D. `7.8xx10^(-5)J`

A spherical drop of water carries a charge of `10xx10^(-12) C` and his a potential of 100V at its surface. Radius of the drop will beA. `9xx10^(-3)m`B. `9xx10^(-5)m`C. `9xx10^(-2)m`D. `9xx10^(-4)m`

A parallel plate capacitor of plate area `0.2 m^2` and spacing `10^(-2)` is charged to `10^(3)V` and is then disconnected from the battery. If the plates are pulled apart to double the plates spacing capacitance of the capacitor will beA. `44.25 pF`B. `88.5 pF`C. `120.45 pF`D. `22.12 pF`

A parallel plate capacitor of plate area `0.2 m^2` and spacing `10^(-2)` is charged to `10^(3)V` and is then disconnected from the battery. If the plates are pulled apart to double the plates spacing Final voltage of the capacitor will beA. `10^(3)V`B. `4xx10^(3)V`C. `2xx10^(3) V`D. `10^(6)V`

Two capacitors `C_1 " and "C_2 (=2C_1)` are connected in a circuit with a switch. Initially, the switch is open and `C_1` holds charge Q. The switch is closed. At steady state, the charge on each capacitor would be A. `Q,2Q`B. `(Q)/(3),(2Q)/(3)`C. `(3Q)/(2),3Q`D. `(2Q)/(3),(4Q)/(3)`

A parallel plate capacitor of plate area `0.2 m^2` and spacing `10^(-2)` is charged to `10^(3)V` and is then disconnected from the battery. Amount of work required to double the plate spacing isA. `8.85xx10^(-5)J`B. `17.7xx10^(-5)J`C. `4.42xx10^(-5)J`D. `26.55xx10^(-7)J`

A capacitor of `4muF` connected as shown in the circuit. The internal resistance of the battery is `0.5 Omega`. The amount of charge on the capacitor plates will be

An `1muF` capacitor C is connected to a battery of 10V through a resistance `1M Omega`. The voltage across C after 1 second is approximatelyA. `56 V`B. `7.8V`C. `6.3V`D. `10V`

A combination is formed by connecting alternately n number of equidistant parallel pltes. If C be the capacitance for any two consecutive plates, then the capacitance of the whose system will beA. `C`B. `nC`C. `(n-1)C`D. `(n+1)C`

A solid spere and a hollow sphere of the same diameter are charged to the same potential. ThenA. The charge on the hollow sphere will be greaterB. Both the spheres will have the same chargeC. only the hollow sphere will be chargedD. the solid sphere will have a greater amount of charge

Five capacitors, each of capacitances C, are connected as in fig. 4.65. The ratio of the capacitance between P and R to that between P and Q is A. `3 : 1`B. `5 : 2`C. `2 : 3`D. `1 : 1`

Find the equivalent capacitance between A and B. A. `5 muF`B. `4 muF`C. `3muF`D. `2 muF`

There are six capacitors in the given network. Capacitance of each is `4 muF`. Effective capacitance between A and B is A. `24 muF`B. `12 muF`C. `(3)/(2)muF`D. `(2)/(3)muF`

The capacity of a parallel plate capacitor is proportional to power n of the distance between the plates. The value of n isA. 1B. 2C. `-1`D. `-2`

A parallel plate capacitor is connected to a battery. The plates are pulled apart with a uniform speed. If x is the separation between the plates, the time rate of change of electrostatic energy of capacitor is proportional toA. `x^(-2)`B. `x`C. `x^(-1)`D. `x^2`

The capacitance of a parallel plate capacitor depends onA. the thickness of the platesB. the charge accumulated on the platesC. the potential difference between the two platesD. the distance between the two plates

The separation between the two plates of a parallel plate capacitor is d. A metal plate of equal area and of thickness `(d)/(2)` is inserted between the two plates. The ratio of the capacitances after and before this insertion isA. `2 : 1`B. `sqrt(2) : 1`C. `1 : sqrt(2)`D. `1 : 2`

A parallel plate capacitor with oil(K=2) has a capacitance C. If the oil is removed, then the capacity of the capacitor becomesA. `sqrt(2)C`B. `2C`C. `(C )/(sqrt(2))`D. `(C )/(2)`

A number of condensers of equal capacity C are arranged in n columns as shown in fig. The equivalent capacity is given by A. `nC`B. `n(n+1)C`C. `(n(n+1))/(2)C`D. `2n(n+1)C`