Electromagnetic Field Theory – MCQs

1. Electromagnetic Field Theory – MCQs: Which law relates the electric field around a closed surface to the charge enclosed?
(A) Ampere’s Law
(B) Faraday’s Law
(C) Gauss’s Law
(D) Coulomb’s Law

2. : The unit of electric field intensity is:
(A) Tesla
(B) Newton
(C) Volt
(D) Volt/meter

3. : What is the direction of the electric field due to a positive point charge?
(A) Tangential
(B) Radially inward
(C) Radially outward
(D) Circular

4. : The magnetic field inside a long solenoid is:
(A) Circular
(B) Zero
(C) Uniform
(D) Increasing

5. : Faraday’s Law relates:
(A) Magnetic field to current
(B) Electric field to voltage
(C) Time-varying magnetic field to induced EMF
(D) Charge to capacitance

6. : The permeability of free space (μ₀) is:
(A) 9 × 10⁹ N·m²/C²
(B) 8.854 × 10⁻¹² F/m
(C) 4π × 10⁻⁷ H/m
(D) 1.6 × 10⁻¹⁹ C

7. : Which equation describes the circulation of the magnetic field around current?
(A) Gauss’s Law
(B) Ampere’s Circuital Law
(C) Faraday’s Law
(D) Lenz’s Law

8. : The divergence of magnetic flux density (B) is:
(A) 1
(B) B
(C) μ₀
(D) 0

9. : Which of the following is not a Maxwell’s Equation?
(A) Gauss’s Law for electricity
(B) Ohm’s Law
(C) Faraday’s Law
(D) Ampere-Maxwell Law

10. : Displacement current was introduced by:
(A) Coulomb
(B) Faraday
(C) Maxwell
(D) Ampere

11. : The electric field due to an infinite line charge varies as:
(A) 1/r
(B) 1/r²
(C) r
(D) Constant

12. : The unit of permittivity (ε) is:
(A) F/m
(B) V/m
(C) C/m
(D) H/m

13. : The Poynting vector represents:
(A) Electric potential
(B) Magnetic flux
(C) Power per unit area
(D) Resistance

14. : The wave impedance of free space is approximately:
(A) 0 Ω
(B) 50 Ω
(C) 120π Ω
(D) 1 Ω

15. : In a perfect conductor, the electric field is:
(A) Infinite
(B) Zero
(C) Constant
(D) Variable

16. : The boundary condition for tangential electric fields at the interface of two media is:
(A) E₁ = E₂
(B) E₁t = E₂t
(C) ε₁E₁ = ε₂E₂
(D) D₁ = D₂

17. : The intrinsic impedance of a medium is defined as:
(A) √(μ/ε)
(B) ε/μ
(C) 1/(μ × ε)
(D) μ × ε

18. : An electromagnetic wave propagating in a lossless medium is:
(A) Dissipative
(B) Uniform
(C) Standing
(D) Transverse

19. : What is the velocity of an EM wave in vacuum?
(A) 10⁸ m/s
(B) 3 × 10⁸ m/s
(C) 2 × 10⁸ m/s
(D) 9.8 m/s²

20. : In a waveguide, which waves are not allowed?
(A) TE
(B) TM
(C) TEM
(D) All of the above

21. : Electric flux density is related to electric field by:
(A) D = εE
(B) D = E/ε
(C) D = μE
(D) D = E/μ

22. : Gauss’s Law for magnetism states that:
(A) Magnetic flux is infinite
(B) Magnetic monopoles exist
(C) Magnetic field lines are open
(D) Magnetic flux through a closed surface is zero

23. : The polarization of a wave indicates:
(A) Its frequency
(B) Direction of magnetic field
(C) Direction of electric field
(D) Its amplitude

24. : Curl of electric field is given by:
(A) ∇ × E = -∂B/∂t
(B) ∇ × E = J
(C) ∇ × E = ∂D/∂t
(D) ∇ × E = 0

25. : Skin effect is observed in:
(A) DC circuits
(B) Static fields
(C) High-frequency AC circuits
(D) Transformers only