Electromagnetic theory miscellaneous
- An uniform plane wave incident normally on a plane surface of dielectric material is reflected with a VSWR of 3 what is the percentage of incident power that is reflected?
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Percentage of reflected power given by
P– R = | Γ |2 Pi+Γ = 3 – 1 ⇒ 2 = 1 3 + 1 4 2 PR– = 1 2 Pi+ 2
so percentage reflected powerPR– × 100 = 1 × 100 = 25% Pi 4 Correct Option: B
Percentage of reflected power given by
P– R = | Γ |2 Pi+Γ = 3 – 1 ⇒ 2 = 1 3 + 1 4 2 PR– = 1 2 Pi+ 2
so percentage reflected powerPR– × 100 = 1 × 100 = 25% Pi 4
- A material has conductivity of 10–2 mho/m and a relative permittivity of 4 the frequency at which conduction current in the medium is equal to the displacement current is—
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As hints are provided in the synopsis that displacement current is the rate of change of electric flux density, so we get
JC = σ E, JD = ∂D ⇒ ωD = ω ε0εr E ∂t
so when both currents are equal
JC = JD ⇒ σE = ω ε0 εr Eω = σ ε0 εr f = σ 2π × 8.85 × 10–12 × 4
= 4.49 × 1010–3 × 1010 = 45 MHzCorrect Option: A
As hints are provided in the synopsis that displacement current is the rate of change of electric flux density, so we get
JC = σ E, JD = ∂D ⇒ ωD = ω ε0εr E ∂t
so when both currents are equal
JC = JD ⇒ σE = ω ε0 εr Eω = σ ε0 εr f = σ 2π × 8.85 × 10–12 × 4
= 4.49 × 1010–3 × 1010 = 45 MHz
- The dominant mode in a rectangular waveguide is TE10 because this mode has—
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For the dominant mode either cut-off frequency should be lowest or cut-off wavelength should be highest.
Correct Option: D
For the dominant mode either cut-off frequency should be lowest or cut-off wavelength should be highest.
- The phase velocity of wave propagating in a hollow metal waveguide is—
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Explained in the synopsis provided.
Correct Option: A
Explained in the synopsis provided.
- If a plane electromagnetic wave satisfies the equation
∂2Ex = e2 ∂2Ex ∂z2 ∂t2
the wave propagates in—
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For the propagation of plane electromagnetic wave their is change in the intensity (magnitude) of wave in the direction of propagation with the time.
Correct Option: B
For the propagation of plane electromagnetic wave their is change in the intensity (magnitude) of wave in the direction of propagation with the time.