Free Electrostatics MCQs with Answers

831 Electrostatics MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.

Electrostatics describes forces between charges through Coulomb's law, electric fields and field intensity, then uses electric potential to measure energy per unit charge. Capacitors store charge and electrical energy, with capacitance depending on geometry and dielectric material, not simply on the amount of charge present.

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831 questions · page 36 of 42

  • A. 1/4th of its original value
  • B. 1/8th of its original value
  • C. 4 times its original value
  • D. 8 times its original value

Explanation: The force between two charges is directly proportional to product of magnitude of chargesF =Kq1q2/r2q1'=2q1 & q2'=2q2F' = (2q1)(2q2)/r2F'=…

Correct answer: 4 times its original value
  • A. Zero
  • B. Infinite
  • C. I-voltm-1
  • D. Negative

Explanation: Electric field intensity = kq/r2 r = infinity E = K q / (infinity)2 E = 0 So the electric field intensity becomes zero at infinity.

Correct answer: Zero
  • A. 1.6
  • B. 1.96
  • C. 1.986
  • D. 1.0006

Explanation: The relative permittivity, or dielectric constant, is a measure of a material's ability to permit electric field lines.

Correct answer: 1.0006
  • A. 104 V
  • B. 105 V
  • C. 106 V
  • D. 107 V

Explanation: To calculate the electric potential at a point due to a point charge, we use the formula: V = kQ/r, where V is the potential, k is…

Correct answer: 105 V
  • A. Potential difference
  • B. Potential energy
  • C. Potential gradient
  • D. All of these

Explanation: Potential gradient is the rate of change of potential difference with distance. It is measured in volts per meter (V/m).

Correct answer: Potential gradient
  • A. Radially inward
  • B. Radially outward
  • C. Radially zero
  • D. None of these

Explanation: A unit positive charge +qo placed in the vicinity of another positive point charge will experience a repulsive force directed radially…

Correct answer: Radially outward
  • A. E
  • B. E2
  • C. 1/E2
  • D. E3

Explanation: The correct answer is that the electrostatic energy density is proportional to E2, where E is the electric field intensity.

Correct answer: E2
  • A. An imaginary surface
  • B. A curved surface
  • C. An open surface
  • D. A plane surface

Explanation: The correct answer is that a Gaussian surface is an imaginary surface. It is a mathematical construct used in electrostatics to apply…

Correct answer: An imaginary surface
  • A. Electric field
  • B. Capacitance
  • C. Energy
  • D. Charge

Explanation: Option D is correct as The quantity that remains unchanged when a dielectric slab is introduced between the plates of a charged parallel…

Correct answer: Charge
  • A. 16 x 10^-5 J
  • B. 32 x 10^-6 J
  • C. 3.2 x 10^-4J
  • D. 16 x 10^-4 J

Explanation: The work done in placing a charge of 8 microcoulombs (μC) on a capacitor of capacitance 100 nanofarads (nF) is 3.2×10-4J .A microcoulomb…

Correct answer: 3.2 x 10^-4J
  • A. The charge will flow from A to B
  • B. The charge will flow from B to A
  • C. No flow of charge will occur
  • D. Both A and B are possible

Explanation: Option A is correct. When metallic spheres A and B, with radii 2m and 4m respectively, carry the same charge and are connected by a copper…

Correct answer: The charge will flow from A to B
  • A. Q only
  • B. V only
  • C. U only
  • D. Q and U only

Explanation: When capacitors are connected in parallel, they share the same potential difference (V) across them, because they are connected directly…

Correct answer: V only
  • A. Q/4, 3Q/4
  • B. Q/3, 2Q/3
  • C. Q/2, Q/2
  • D. Q/5, 4Q/5

Explanation: To find the value of charge that should be placed on each sphere so that the force of attraction between them is maximum, we can use the…

Correct answer: Q/2, Q/2
  • A. C N-1 M-1
  • B. watt K-1 mol-1
  • C. C2N-1M-2
  • D. joule C-1 mol-1

Explanation: Option C is correct because the SI unit of Vacuum Permittivity (ε0) is C2 N-1 M-2 and its value is approximately 8.85 x 10-12.

Correct answer: C2N-1M-2
  • A. (1+a)m from 4Q
  • B. a/2 m from - Q
  • C. 1m from 4Q
  • D. Neutral point hence not possible

Explanation: Following is the solution to this question:

Correct answer: (1+a)m from 4Q
  • A. 4C
  • B. 2C
  • C. C/2
  • D. C/4

Explanation: Before the metal sheet is inserted, C = εo A/d After the sheet is inserted, the system is equivalent to two capacitors in series, each of…

Correct answer: 2C
  • A. Option A
  • B. Option B
  • C. Option C
  • D. Option D

Explanation: When a point charge q is placed at a distance r from the center of an uncharged conducting sphere of radius R (where R < r), the potential…

Correct answer: Option B
  • A. KQ1Q2Q3
  • B. 4KQ1Q2
  • C. 4KQ2Q3
  • D. 2/3 KQ2Q3.

Explanation: Following is the solution to this question in the image:

Correct answer: 4KQ2Q3