## MCQ on Maxwell’s equations

MCQ on Maxwell’s equations, Maxwell’s equations objective Question with answers, Gate Objective Question on Maxwell’s equations, Multiple Choice Questions on Maxwell’s equations, MCQ on Displacement current, Maxwell’s equations question and answer, GATE questions on Maxwell’s equations

### Multiple Choice Questions

Q.1. Maxwell’s equations shelter on __________ law(s).

- Faraday’s
- Gauss’s
- Ampere’s
- All of these

**Answer: **All of these

Q.2. Conduction current through a wire is __________ displacement current in capacitor.

- Same as
- Different from

- Twice of

- None of these

**Answer: **Same as

Q.3. Absolute permeability of free space is

- 4π × 10
^{-7}A/m - 4π × 10
^{-7}H/m - 4π × 10
^{-7}F/m - 4π × 10
^{-7}H/m^{2}

**Answer: **4π × 10^{-7} H/m

Q.4. For static magnetic field,

- ∇ ×
**B**= ρ - ∇ ×
**B**= μ**J** - ∇ ×
**B**= μ_{0}**J** - ∇ ×
**B**= 0

**Answer: **∇ × **B** = μ**J**

Q.5. The time varying electric field is

**E**= − ∇V**E**= − ∇V −**Ȧ****E**= − ∇V –**B****E**= − ∇V –**D**

**Answer: ****E** = − ∇V − **Ȧ**

Q.6. Maxwell’s third equation gives __________.

- \bigtriangledown \times \vec{H}=\vec{J_{d}}+\frac{\partial \rho }{\partial t}
- \bigtriangledown \cdot \vec{H}=J_{d}\frac{\partial \rho }{\partial t}
- \bigtriangledown \cdot \vec{H}=\vec{J_{d}}+\frac{\partial \rho }{\partial t}
- \bigtriangledown \times \vec{H}=J_{d}\frac{\partial \rho }{\partial t}

**Answer: **\bigtriangledown \times \vec{H}=\vec{J_{d}}+\frac{\partial \rho }{\partial t}

Q.7. Maxwell’s fourth equation gives __________.

- \bigtriangledown \cdot \vec{E}=-\frac{\partial \vec{B} }{\partial t}
- \bigtriangledown \times \vec{E}=-\frac{\partial \vec{B} }{\partial t}
- \bigtriangledown \cdot \vec{E}=\frac{\partial \vec{B} }{\partial t}
- \bigtriangledown \times \vec{E}=\frac{\partial \vec{B} }{\partial t}

**Answer: **\bigtriangledown \times \vec{E}=-\frac{\partial \vec{B} }{\partial t}

Q.8. In empty space, conduction current is __________.

- Infinity

- Unity
- Zero
- None of these

**Answer: **Zero

Q.9. As per Maxwell’s first equation __________.

- \bigtriangledown \times \vec{D}=\rho _{\nu }
- \bigtriangledown \cdot \vec{D}=\rho _{\nu }
- \bigtriangledown \times \vec{D}=\rho _{s }
- \bigtriangledown \cdot \vec{D}=\rho _{s }

**Answer: **\bigtriangledown \cdot \vec{D}=\rho _{\nu }

Q.10. Maxwell’s second equation gives __________.

- \bigtriangledown \times \vec{B}=0
- \bigtriangledown \cdot \vec{B}=0
- \bigtriangledown \times \vec{B}=1
- \bigtriangledown \cdot \vec{B}=1

**Answer: **\bigtriangledown \cdot \vec{B}=0

Q.11. emf is closed __________ integral of non-conservational electric field that is generated by battery.

- Line
- Surface
- Volume
- None of these

**Answer: **Line

Q.12. Maxwell’s equations in __________ form give unformation at points of discontinuity in electromagnetic fields.

- Differential
- Integral
- Algebraic
- None of these

**Answer: **Integral

Q.13. At the point of discontinuity, __________ component of magnetic flux density is continuous.

- Tangential
- Normal
- None of these
- Cannot say

**Answer: **Normal

Q.14. For those surfaces where surface charge density is __________ normal component of electric flux density is continuous.

- Infinity
- Unity
- Zero
- None of these

**Answer: **Zero

Q.15. Displacement current density ____________ current passing through a capacitor.

- Represents
- Does not represent
- Is the same as
- None of these

**Answer: **Does not represent

Q.16. Line integral of an electric field around a closed path is __________.

- Infinity
- Unity
- Zero
- None of these

**Answer: **Zero

Q.17. __________ are caused by accelerated charges.

- Time-varying fields
- Waves
- Both Time-varying fields & Waves
- None of these

**Answer: **Both Time-varying fields & Waves

Q.18. Maxwell’s equations give the relations between

- different fields
- different sources
- different boundary conditions
- none of these

**Answer: **different fields

Q.19. cosine of the angle between the two vectors is

- sum of the products of the directions of the two vectors
- difference of the products of the directions of the two vectors
- product of the products of the directions of the two vectors
- none of these

**Answer: **sum of the products of the directions of the two vectors

Q.20. The electric field intensity, E at a point (1, 2, 2) due to (1/9) nc located at (0, 0, 0) is

- 33 V/m
- 0.333 V/m
- 0.33 V/m
- Zero

**Answer: **0.33 V/m

Q.21. If **E** is a vector, then ∇ . ∇ × **E** is

- 0
- 1
- does not exist
- none of these

**Answer: **0

Q.22. For free space,

- σ = ∞
- σ =0
- J ≠ 0
- none of these

**Answer: **σ =0

Q.23. The electric field for time varying potentials

- E = − ∇V
- E = − ∇V –
**A** - E = ∇V
- E = − ∇V +
**A**

**Answer: **E = − ∇V

Q.24. The intrinsic impedence of the medium whose σ = 0, ∈_{r} = 9, μ_{r} = 1 is

- 40 πΩ
- 9 Ω
- 120 πΩ
- 60 πΩ

**Answer: **40 πΩ

Q.25 For time varying EM fields

- ∇ ×
**H**=**J** - ∇ ×
**H**=**Ḋ**+**J** - ∇ ×
**E**= 0 - none of these

**Answer: **∇ × **H** = **Ḋ** + **J**

Q.26. The wavelength of a wave with a propagation constant = 0.1π + j 0.2π is

- 10 m
- 20 m
- 30 m
- 25 m

**Answer: **10 m

Q.27. The electric field just above a conductor is always

- normal to the surface
- tangential to source
- zero
- ∞

**Answer: **normal to the surface

Q.28. The normal components of D are

- continuous across a dielectric boundary
- discontinuous across a dielectric boundary
- zero
- ∞

**Answer: **continuous across a dielectric boundary

Q.29. If J_{c} = 1 mA/m^{2} in a medium whose conductivity is σ = 10 Mho/m, E is

- 0.1 V/m
- 10μ V/m
- 1.0μ V/m
- 10 V/m.

**Answer: **0.1 V/m

Q.30. If J_{d} = 2 mA/m^{2} in a medium whose ∈_{r} = 2, σ= 4.95 Mho/m at a frequency of 1 GHz, J_{c} is

- 8.9 mA/m
^{2} - 89 mA/m
^{2} - 0.89 mA/m
^{2} - 89 A/m
^{2}

**Answer: **89 mA/m^{2}