Electrostatic Potential And Capacitance

15 Questions | By Jagranjosh | Updated: Mar 22, 2022 | Attempts: 2701

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Electrostatic Potential And Capacitance - Quiz

Time: 30 Minute

Questions and Answers

1.

A parallel plate capacitor has a capacitance of 50 pf in air and 105 pf when immersed in oil. The dielectric constant of the oil is:
- A.
  
  50/105
- B.
  
  1
- C.
  
  2.1
- D.
2.

Three capacitors of capacitance 4µ F, 6µF and 12µF are connected first in series and then in parallel. What is the ratio of equivalent capacitance in the two cases?
- A.
  
  2 : 3
- B.
  
  1 : 11
- C.
  
  11 : 1
- D.
  
  1 : 3
3.

A work of 100 joule is performed in carrying a charge of -5 coulomb from infinity to a particular point in an electrostatic field. The potential of this point is:
- A.
  
  100 V
- B.
  
  5 V
- C.
  
  -20 V
- D.
  
  20 V
4.

When air is replaced by a dielectric medium of constant K, the maximum force of attraction between two charges separated by a distance:
- A.
  
  Becomes times
- B.
  
  Increases K times
- C.
  
  Remains unchanged
- D.
  
  Decreases K times
5.

Potential energy of two equal negative point charges 2µC each held 1m apart in air is:
- A.
  
  2 J
- B.
  
  2 eV
- C.
  
  4 J
- D.
  
  0.036 J
6.

The electric potential at the surface of an atomic nucleus (Z = 50) of radius 9.0 x 10^-15 m is:
- A.
  
  80 volt
- B.
  
  8 x volt
- C.
  
  9 volt
- D.
  
  9 x volt
7.

Three different capacitors are connected in series. Then:
- A.
  
  They will have equal charges
- B.
  
  They will have same potential
- C.
  
  Both 1 & 2
- D.
  
  None of these
8.

A 2µF capacitor is charged to 100 volt and then its plates are connected by a conducting wire. The heat produced is:
- A.
  
  0.001 J
- B.
  
  0.01 J
- C.
  
  0.1 J
- D.
  
  1 J
9.

A hollow metal sphere of radius 10 cm is charged such that the potential on its surface is 80 volt. The potential at the centre of the sphere is:
- A.
  
  8 volt
- B.
  
  800 volt
- C.
  
  80 volt
- D.
  
  Zero
10.

A parallel plate capacitor is made by stocking n equally spaced plates connected alternately. If the capacitance between any two plates is x, then the total capacitance is:
- A.
  
  Nx
- B.
  
  N/x
- C.
  
  X
- D.
  
  (n – 1) x
11.

The equivalent capacity of the combination C₁ = C₂ = C₃ shown in figure is:
- A.
  
  2 C
- B.
  
  C
- C.
  
  C / 2
- D.
  
  None of these
12.

Three capacitors each of capacity 4 µF are to be connected in such a way that the effective capacitance is 6 µF. This can be done by:
- A.
  
  Connecting all of them in series
- B.
  
  Connecting all of them in parallel
- C.
  
  Connecting two in series and one in parallel
- D.
  
  Connecting two in parallel and one in series
13.

The magnitude of electric field E in the annular region of a charged cylindrical capacitor.
- A.
  
  Is the same throughout
- B.
  
  Is higher near the outer cylinder than near the inner cylinder
- C.
  
  Varies as 1/r, where r is the distance from the axis
- D.
  
  Varies as 1/ , where r is the distance from the axis.
14.

A 800 µF capacitor is charged at the steady rate of 50 µC/sec. How long will it take to raise its potential to 10 volt?
- A.
  
  160 s
- B.
  
  50 s
- C.
  
  10 s
- D.
  
  500 s
15.

If there are n capacitors in parallel connected to V volt source, then energy stored is equal to:
- A.
  
  CV
- B.
  
  C
- C.
- D.
  
  nC