Physics

Electrostatics

299 Questions

Electrostatics deals with electric charges, fields, and potentials at rest. It is a crucial topic for physics sections in engineering and civil services competitive examinations. Review these questions to build a strong understanding of Coulomb law, electric dipoles, Gauss law, and electric flux.

Electric field and potentialElectric dipole momentGauss Law applicationsCoulomb force calculationsCharge distribution on spheresEquipotential surfaces

Electrostatics Questions

Multiple choice

What is the mathematical form of Gauss's law for electric fields?

  1. $\nabla \cdot E = \rho$
  2. $\nabla \cdot B = 0$
  3. $\nabla \times E = -\frac{\partial B}{\partial t}$
  4. $\nabla \times B = \mu_0 (J + \epsilon_0 \frac{\partial E}{\partial t})$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Gauss's law for electric fields states that the divergence of the electric field is proportional to the electric charge density.

Multiple choice

What is the name of the constant that appears in Ampère's circuital law with Maxwell's addition?

  1. Permittivity of free space

  2. Permeability of free space

  3. Speed of light

  4. Elementary charge
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The constant that appears in Ampère's circuital law with Maxwell's addition is the permeability of free space, denoted by (\mu_0).

Multiple choice

What is the name of the constant that appears in Gauss's law for electric fields?

  1. Permittivity of free space

  2. Permeability of free space

  3. Speed of light

  4. Elementary charge
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The constant that appears in Gauss's law for electric fields is the permittivity of free space, denoted by (\epsilon_0).

Multiple choice

Which of Maxwell's equations is responsible for the force between two electric charges?

  1. Gauss's law for electric fields

  2. Gauss's law for magnetic fields

  3. Faraday's law of induction

  4. Ampère's circuital law with Maxwell's addition
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Gauss's law for electric fields describes the force between two electric charges, which is proportional to the product of the charges and inversely proportional to the square of the distance between them.

Multiple choice

What is the name of the constant that appears in Ampère's circuital law?

  1. Permittivity of free space

  2. Permeability of free space

  3. Speed of light

  4. Elementary charge
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The constant that appears in Ampère's circuital law is the permeability of free space, denoted by (\mu_0).

Multiple choice

Gauss's Law states that the electric flux through any closed surface is proportional to the total charge enclosed by the surface. What is the proportionality constant?

  1. 1/ε0

  2. ε0

  3. 4πε0

  4. -4πε0
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The proportionality constant in Gauss's Law is 1/ε0, where ε0 is the permittivity of free space.

Multiple choice

A point charge of +1 μC is placed at the center of a spherical surface of radius 10 cm. What is the electric flux through the surface?

  1. 100 N⋅m^2/C

  2. 10 N⋅m^2/C

  3. 1 N⋅m^2/C

  4. 0.1 N⋅m^2/C
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The electric flux through a spherical surface of radius r due to a point charge q at the center is given by Φ = q/ε0. Substituting the values, we get Φ = (1 μC)/(8.85 × 10^-12 C^2/Nm^2) = 100 N⋅m^2/C.

Multiple choice

A uniform electric field of 100 N/C is applied to a rectangular surface of area 0.2 m^2. What is the electric flux through the surface?

  1. 20 N⋅m^2/C

  2. 2 N⋅m^2/C

  3. 0.2 N⋅m^2/C

  4. 0.02 N⋅m^2/C
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The electric flux through a surface is given by Φ = EA, where E is the electric field strength and A is the area of the surface. Substituting the values, we get Φ = (100 N/C)(0.2 m^2) = 20 N⋅m^2/C.

Multiple choice

Gauss's Law can be used to calculate the electric field of a charge distribution. What is the electric field of a uniformly charged sphere?

  1. E = kQ/r^2

  2. E = kQ/r

  3. E = kQr

  4. E = kQ/r^3
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The electric field of a uniformly charged sphere is given by E = kQ/r^2, where k is Coulomb's constant, Q is the total charge of the sphere, and r is the distance from the center of the sphere.

Multiple choice

Gauss's Law can be used to calculate the electric potential of a charge distribution. What is the electric potential of a point charge?

  1. V = kQ/r

  2. V = kQ/r^2

  3. V = kQr

  4. V = kQ/r^3
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The electric potential of a point charge is given by V = kQ/r, where k is Coulomb's constant, Q is the charge of the point charge, and r is the distance from the point charge.

Multiple choice

A hollow conducting sphere of radius R has a charge Q. What is the electric field inside the sphere?

  1. E = 0

  2. E = kQ/R

  3. E = kQ/R^2

  4. E = kQ/R^3
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The electric field inside a hollow conducting sphere is zero.

Multiple choice

A solid conducting sphere of radius R has a charge Q. What is the electric field inside the sphere?

  1. E = 0

  2. E = kQ/R

  3. E = kQ/R^2

  4. E = kQ/R^3
Reveal answer Fill a bubble to check yourself
Correct answer
Explanation

The electric field inside a solid conducting sphere is given by E = kQ/r, where r is the distance from the center of the sphere.

Multiple choice

Gauss's Law is a fundamental law of electromagnetism. What is the significance of Gauss's Law?

  1. It relates the electric field to the charge distribution.

  2. It relates the magnetic field to the current distribution.

  3. It relates the electric field to the magnetic field.

  4. It relates the charge distribution to the current distribution.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Gauss's Law relates the electric field to the charge distribution. It states that the electric flux through any closed surface is proportional to the total charge enclosed by the surface.

Multiple choice

Gauss's Law is a powerful tool for solving electrostatics problems. What are some applications of Gauss's Law?

  1. Calculating the electric field of a charge distribution.

  2. Calculating the electric potential of a charge distribution.

  3. Calculating the capacitance of a capacitor.

  4. Calculating the inductance of a solenoid.
Reveal answer Fill a bubble to check yourself
Correct answer
Explanation

Gauss's Law can be used to calculate the electric field of a charge distribution, the electric potential of a charge distribution, the capacitance of a capacitor, and the inductance of a solenoid.