Olete.in – MCQs, Mock Tests & Government Job Prep | Electrical engineering Microwave Engineering MCQs Set-2

If a transmission line is exited from a source of 4V at 1.2GHz frequency with a generator impedance of 4+j3 with a characteristic impedance of the transmission line 50Ω,then the power delivered to the load is:

1. 0.1 watt
2. 0.9 watt
3. 0.8 watt
4. 1watt

✅ Correct Answer: 3

If the generator impedance of a source connected to a transmission line is 50+j100Ω, then for conjugate matching to occur, the input impedance must be:

1. 50-j100 Ω
2. 50+100 Ω
3. 50 Ω
4. one of the mentioned

✅ Correct Answer: 1

After conjugate impedance matching the input impedance used for matching after normalization was 1+j with the characteristic impedance of the transmission line being 100Ω, then the generator impedance must have been:

1. 100+100j
2. 1+j
3. 100-100j
4. 1-j

✅ Correct Answer: 3

For a matched transmission line with a generator impedance of 50Ω and the source being 4V,1GHZ,then the maximum power delivered to the line is:

1. 0.4 watt
2. 0.04 watt
3. 0.5 watt
4. no power is delivered

✅ Correct Answer: 2

If the power delivered to a load is 0.04w, then the normalized generator impedance if the source use is 4V at 2GHz and the generator impedance is real and characteristic impedance of the transmission line is 50Ω is:

1. 1 Ω
2. 1+j Ω
3. 1-j Ω
4. 50 Ω

✅ Correct Answer: 1

For a low loss line when both conductor and di-electric loss is small, the assumption that could be made is:

1. R < < ωL and G < < ωC
2. R > > ωL and G > >ωC
3. R < <ωC and G < < ωL
4. R > >ωC and G > >ωL

✅ Correct Answer: 1

Expression for α(attenuation constant) in terms of R , G, L and C of a transmission line is:

1. (R√(C/L)+G√(L/C))0.5
2. (R√(C/L)+G√(L/C))
3. (R√(L/C)+G√(C/L))
4. (R√(L/C)+G√(C/L))0.5

✅ Correct Answer: 1

Expression for characteristic impedance Zₒ of a transmission line in terms of L and C the transmission line is:

1. √(C/L)
2. √(CL)
3. √(L/C)
4. 1/√(LC)

✅ Correct Answer: 3

If the inductance and capacitance of a loss line transmission line are 45 mH/m and10 µF/m, the characteristic impedance of the transmission line is:

1. 50Ω
2. 67.08Ω
3. 100Ω
4. none of the mentioned

✅ Correct Answer: 2

If the characteristic impedance of a transmission line is 50 Ω, and the inductance of the transmission line being 25 mH/m, the capacitance of the lossy transmission line is:

1. 1µF
2. 10 µF
3. 0.1 µF
4. 50 µF

✅ Correct Answer: 2

If R = 1.5Ω/m, G = 0.2 mseimens/m, L = 2.5 nH/m, C = 0.1 pF/m for a low loss transmission line, then the attenuation constant of the transmission line is:

1. 0.0.158
2. 0.0523
3. 0.0216
4. 0.0745

✅ Correct Answer: 1

A lossy line that has a linear phase factor as a function of frequency is called:

1. distortion less line
2. terminated lossy line
3. loss less line
4. lossy line

✅ Correct Answer: 1

The condition for a distortion less line is:

1. R/L=G/C
2. R/C=G/L
3. R=G
4. C=L

✅ Correct Answer: 1

For a distortion less line, R= 0.8Ω/m, G= 0.8 msiemens/m, L= 0.01µH/m then C is:

1. 10 pF
2. 1pF
3. 1nF
4. 10nF

✅ Correct Answer: 1

For a lossy transmission line, γ=0.02+j0.15 and is 20m long. The line is terminated with an impedance of a 400Ω. Then the input impedance of the transmission line given that the characteristic impedance of the transmission line is 156.13+j11.38Ω is:

1. 100+j50 Ω
2. 228+j36.8 Ω
3. 50+36.8j Ω
4. none of the mentioned

✅ Correct Answer: 2

Maxwell’s equation for electromagnetic waves in a waveguide is:

1. ∇×E = -jωµ(vector H)
2. ∇×E =-jωμ(vector E)
3. ∇×H=-jωμ(vector H)
4. ∇×H=jωμ(vector H)

✅ Correct Answer: 1

If the wavelength of a signal is 10 mm, then the wavenumber of the material when a waveguide is filled with that material is:

1. 628
2. 345
3. 123
4. None of the mentioned

✅ Correct Answer: 1

If a waveguide is filled with a lossless material of relative permeability 2, then the wave impedance in the TEM mode is:

1. 188.5 Ω
2. 170 Ω
3. 123 Ω
4. 345 Ω

✅ Correct Answer: 1

If the wave impedance of a medium is 200 Ω, then what is the relative permittivity of that medium?

1. 1.885
2. 2
3. 2.2
4. 2.5

✅ Correct Answer: 1

If p=0.3 and the wave number of air in TM mode is 16, then the intrinsic impedance of air in TM mode given wave number is 125 is:

1. 1 Ω
2. 0.9 Ω
3. 0.8 Ω
4. 2 Ω

✅ Correct Answer: 2

If the intrinsic impedance of a medium is 0.8 Ω, with wave number 125 and β being 0.2, then the relative permeability of the medium is:

1. 1.326
2. 2.34
3. 4.5
4. 6.7

✅ Correct Answer: 1

The losses that occur in a transmission line is:

1. Conduction losses
2. Di-electric loss
3. Both of the mentioned
4. None of the mentioned

✅ Correct Answer: 3

Which of the following is true regarding attenuation?

1. Conductor loss
2. Di-electric loss
3. Sum of both conductor loss and di electric loss
4. Attenuation is different from the losses

✅ Correct Answer: 3

If the wave number of a medium is 20 and loss tangent is 0.4 , then the dielectric loss caused by the medium is:

1. 4
2. 2
3. 3
4. 6

✅ Correct Answer: 1

If the dielectric loss of a medium is 0.2 Np/m with a wave number of 12, then the value of loss tangent is:

1. 0.0334
2. 0.05
3. 0.08
4. 0.09

✅ Correct Answer: 1

The modes of wave propagation that a parallel plate waveguide can support are:

1. TEM, TE, TM modes
2. TM, TE modes
3. TEM, TM modes
4. TEM, TE modes

✅ Correct Answer: 1

The fringe effect can be neglected in a parallel plate waveguide is because of:

1. The dielectric material used
2. Width of the plates is greater than the distance between the plates
3. Material of the parallel plate waveguide used
4. None of the mentioned

✅ Correct Answer: 2

The characteristic impedance of a parallel plate waveguide is given by:

1. η*D/W
2. η*W/D
3. D/ η*W d) η*√(D/W)
4.

✅ Correct Answer: 1

If the width of a parallel plate waveguide is 30 mm and the distance between the parallel pates is 5 mm, with an intrinsic impedance of 377Ω, then the characteristic impedance of the wave is:

1. 50 Ω
2. 62.833 Ω
3. 100 Ω
4. None of the mentioned

✅ Correct Answer: 2

The wave impedance of a TM mode in a parallel plate waveguide is a:

1. Function of frequency
2. Independent of frequency
3. Proportional to square of frequency
4. Inversely proportional to square of frequency

✅ Correct Answer: 1

In a parallel plate waveguide, for a propagating mode, the value of β is:

1. Real
2. Complex
3. Imaginary
4. Cannot be defined

✅ Correct Answer: 1

For TM2 mode, if the distance between two parallel plates of a waveguide are 40 mm, then the cut off wavelength for TM2 mode is:

1. 20 mm
2. 80 mm
3. 40 mm
4. 60 mm

✅ Correct Answer: 3

For a parallel waveguide, the dominant mode for TM propagation is:

1. TM0 mode
2. TM1 mode
3. TM2 mode
4. Dominant mode does not exist

✅ Correct Answer: 2

Phase velocity of the plane waves in the two direction in a parallel plate waveguide is:

1. 1/√(μ∈)secant θ
2. 1/√(μ∈)cosecant θ
3. 1/√(μ∈)tangent θ
4. 1/√(μ∈)cosine θ

✅ Correct Answer: 1

For a parallel plate waveguide, which of the following is true?

1. No real power flow occurs in the ‘z’ direction
2. Power flow occurs in ‘z’ direction
3. No power flow occurs in any direction
4. Wave propagation in z direction is not possible in any mode

✅ Correct Answer: 1

The wave impedance for a non-propagating mode in TE mode is:

1. K/β
2. Imaginary
3. Zero
4. Non-existing

✅ Correct Answer: 2

The modes of propagation supported by a rectangular wave guide is:

1. TM, TEM, TE modes
2. TM, TE
3. TM, TEM
4. TE, TEM

✅ Correct Answer: 2

A hollow rectangular waveguide cannot propagate TEM waves because:

1. Of the existence of only one conductor
2. Of the losses caused
3. It is dependent on the type of the material used
4. None of the mentioned

✅ Correct Answer: 1

For any mode of propagation in a rectangular waveguide, propagation occurs:

1. Above the cut off frequency
2. Below the cut off frequency
3. Only at the cut-off frequency
4. Depends on the dimension of the waveguide

✅ Correct Answer: 1

Dominant mode is defined as:

1. Mode with the lowest cut off frequency
2. Mode with the highest cut off frequency
3. Any TEM mode is called a dominant mode
4. None of the mentioned

✅ Correct Answer: 1

For dominant mode propagation in TE mode, if the rectangular waveguide has a broader dimension of 31.14 mm , then the cutoff wave number:

1. 100
2. 500
3. 50
4. 1000

✅ Correct Answer: 1

The lowest mode of TM wave propagation is:

1. TM10 mode
2. TM01 mode
3. TM11 mode
4. TM12 mode

✅ Correct Answer: 2

The cutoff frequency for the dominant mode in TM mode propagation for a rectangular waveguide of dimension of 30mm*40mm is:

1. 2 GHz
2. 1 GHz
3. 2 MHz
4. 4 MHz

✅ Correct Answer: 1

In TE10 mode of wave propagation in a rectangular waveguide, if the broader dimension of the waveguide is 40 cm, then the cutoff wavelength for that mode is:

1. 8 cm
2. 6 cm
3. 4 cm
4. 2 cm

✅ Correct Answer: 1

In TE01 mode of wave propagation in a rectangular waveguide, if the smaller dimension of the waveguide is 2 cm, then the cutoff wavelength for that mode is:

1. 4 cm
2. 8 cm
3. 1 cm
4. 2 cm

✅ Correct Answer: 1

The lowest mode of TE mode propagation in a circular waveguide is:

1. TE10 mode
2. TE00 mode
3. TE01 mode
4. TE11 mode

✅ Correct Answer: 3

For a circular waveguide in TM11 mode of propagation with inner radius of 30mm, and the phase constant being equal to 0.3, then the wave impedance is equal to:

1. 0.16 Ω
2. 0.15 Ω
3. 0.5 Ω
4. 0.4 Ω

✅ Correct Answer: 1

In TM mode, what is the first propagating mode?

1. TM01 mode
2. TM11 mode
3. TM12 mode
4. TM10 mode

✅ Correct Answer: 1

The cutoff frequencies of the first two propagating modes of a Teflon on a filled circular waveguide with a=0.5 with ∈r=2.08 is:

1. 12.19 GHz, 15.92 GHz
2. 10 GHz, 12 GHz
3. 12 GHz, 15 GHz
4. 15 GHz, 12 GHz

✅ Correct Answer: 1

What are the modes of propagation that a co axial line supports?

1. TM, TE mode
2. TM, TE, TEM mode
3. TM, TEM mode
4. TE, TEM mode

✅ Correct Answer: 2