BEE Bachelor of Electrical Engineering Electromagnetic Fields and Waves Questions and Answers Flashcards

What is the skin depth formula for a good conductor at angular frequency ω?

Answer: √(2/(ωμσ))

Skin depth δ = √(2/(ωμσ)), showing that higher frequency or conductivity results in shallower penetration.

Which of Maxwell's equations introduces the displacement current concept?

Answer: Ampere's law with Maxwell's correction

Maxwell added the displacement current term ∂D/∂t to Ampere's law to ensure consistency with the continuity equation.

A linearly polarized wave has its electric field oriented in the x-direction and propagates in the z-direction. What is the orientation of the magnetic field?

Answer: y-direction

For a plane wave propagating in z with E in x, H must be in the y-direction to satisfy E × H pointing in z.

What is the intrinsic impedance of free space?

Answer: 377 Ω

The intrinsic impedance of free space is η₀ = √(μ₀/ε₀) ≈ 377 Ω (or equivalently 120π Ω).

When an electromagnetic wave strikes a perfect conductor at normal incidence, what is the reflection coefficient?

Answer: -1

A perfect conductor reflects all incident energy with a phase reversal, giving a reflection coefficient of -1.

What physical law does Faraday's law in Maxwell's equations describe?

Answer: A time-varying magnetic field induces an electric field

Faraday's law states that a changing magnetic flux through a surface induces a circulating electric field along its boundary.