Class 12 Electrostatic Potential And Capacitance CBSE Questions & Answers

Class 12 · Electrostatic Potential And Capacitance

This is Physics Class 12 Electrostatic Potential and Capacitance CBSE Questions & Answers. There are 15 questions in this test with each question having around four answer choices.

Questions & Answers

1
The electric dipole potential falls off, at large distance r
  • A
    as \({\rm{1}}/{{\rm{r}}^{{\rm{1}}.{\rm{4}}}}\)
  • B
    as \({\rm{1}}/{{\rm{r}}^{{\rm{3}}.0}}\)
  • C
    as \({\rm{1}}/{{\rm{r}}^{{\rm{2}}.0}}\)
    Correct
  • D
    as \({\rm{1}}/{{\rm{r}}^{{\rm{1}}.{\rm{8}}.0}}\)
2
An equipotential surface is a surface
  • A
    on which the potential has the same value at every point
    Correct
  • B
    on which the potential has negative value at every point
  • C
    on which the potential has the zero value at every point
  • D
    on which the potential has positive value at every point
3
Which of the following is true about equipotential lines
  • A
    Electric field lines are parallel to equipotential lines
  • B
    Electric field lines are tangential to equipotential lines
  • C
    Electric field lines are opposite to equipotential lines
  • D
    Electric field lines are perpendicular to equipotential lines
    Correct
4
At the surface of a charged conductor, electrostatic field must be
  • A
    never normal to the surface at every point
  • B
    normal to the surface at every point
    Correct
  • C
    parallel to the surface at every point
  • D
    tangential to the surface at every point
5
Electrostatic shielding is based
  • A
    electric field inside the cavity of a conductor is zero
    Correct
  • B
    electric field inside the cavity of a conductor is greater than zero
  • C
    electric field inside the cavity of a conductor is less than zero
  • D
    electric field inside the cavity of a plastic is zero
6
Capacitance is defined as
  • A
    \({\rm{charg}}{{\rm{e}}^{{\rm{2}}.0}}/{\rm{ voltage}}\)
  • B
    charge/voltage
    Correct
  • C
    \({\rm{charge}}/{\rm{voltag}}{{\rm{e}}^{{\rm{2}}.0}}\)
  • D
    charge \( \times \) voltage
7
Correct formula for capacitance in terms of area A and distance d,of a parallel plate capacitor in vacuum is
  • A
    \(\epsilon_0\frac{A^2}{d}\)
  • B
    \(\epsilon_0\frac{A}{d}\)
    Correct
  • C
    \(\epsilon_0\frac{A}{d^2}\)
  • D
    \(\epsilon_0\frac{d}{A}\)
8
when two capacitors are put in series, the equivalent capacitance is
  • A
    the sum of the capacitances
  • B
    the product of the capacitances
  • C
    the reciprocal of the capacitances
  • D
    smaller than both capacitances
    Correct
9
For a parallel plate capacitor ______________ possible potential difference between the capacitor plates
  • A
    dielectric increases the minimum
  • B
    dielectric increases the maximum
  • C
    dielectric decreases the minimum
  • D
    dielectric decreases the maximum
    Correct
10
For a parallel plate capacitor and a dielectric of dielectric constant K When a dielectric material is inserted between the plates while_______________ the potential difference between the plates decreases by a factor K
  • A
    the charge is increased,
  • B
    the charge is decreased,
  • C
    the charge is increased,
  • D
    the charge is kept constant,
    Correct
11
The dielectric constant K of an insulator can be
  • A
    -4.0
  • B
    0.4
  • C
    0.0
  • D
    4.0
    Correct
12
The dielectric constant K of an insulator cannot be
  • A
    9
  • B
    4
  • C
    infinity
    Correct
  • D
    6
13
If the dielectric constant and dielectric strength be denoted by K and X respectively, then a material suitable for use as a dielectric in a capacitor must have
  • A
    low K and high X
  • B
    low K and low X.
  • C
    high K and low X
  • D
    high K and high X
    Correct
14
If one penetrates a uniformly charged metallic sphere, the electric field strength E
  • A
    is zero at all points
  • B
    remains the same as at the surface
  • C
    Decreases
    Correct
  • D
    increases
15
A parallel plate condenser is immersed in an oil of dielectric constant 2. The field between the plates is
  • A
    decreased proportional to 1/2
    Correct
  • B
    increased proportional to \(\sqrt 2 \)
  • C
    decreased proportional to \({1 \over {\sqrt 2 }}\)
  • D
    increased proportional to 2