BEE Engineering Electromagnetics Fundamentals 3

Question 1

Stokes' theorem relates a surface integral of the curl of a vector field to:

Accepted Answer

A line integral around the bounding contour

Answer

Stokes' theorem states ∬(∇×A)·dS = ∮A·dl, converting a surface integral to a closed line integral.

Question 2

For a uniform plane wave propagating in the +z direction, if E is in the x̂ direction, then H is in the direction:

Accepted Answer

+ŷ

Answer

For a +z propagating wave, E × H must point in +z, so H = ŷ (since x̂ × ŷ = ẑ).

Question 3

The inductance per unit length of a two-wire transmission line with wire radius a and separation d (d >> a) is approximately:

Accepted Answer

μ ln(d/a) / π

Answer

For a two-wire line, L/l = (μ/π) ln(d/a), derived from the magnetic flux linkage per unit length.

Question 4

In electrostatics, Laplace's equation ∇²V = 0 applies in regions where:

Accepted Answer

There is no free charge density

Answer

Laplace's equation holds in source-free regions (ρᵥ = 0), while Poisson's equation applies where ρᵥ ≠ 0.

Question 5

The reflection coefficient Γ at a transmission line load is defined as:

Accepted Answer

Γ = (Z_L - Z₀) / (Z_L + Z₀)

Answer

The voltage reflection coefficient is Γ = (Z_L − Z₀)/(Z_L + Z₀), determining the reflected wave amplitude.

BEE - Bachelor of Electrical Engineering Practice Test