Q. In a circular waveguide TE₂₁ mode has lowest cutoff frequency

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Q. The number of TV channels which can be accommodated in a spectrum of 300 MHz is about

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Q. The noise figure of multicavity klystron amplifier is very low

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Q. Assertion (A): The velocity of electromagnetic waves on overhead lines and coaxial cables is the same.

Reason (R): Free space has an intrinsic impedance of 377 ohms.

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Q. A cavity resonator is

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Q. If antenna diameter is increased four times, the maximum range is increased by a factor of

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Q. Assertion (A): Gunn diode is a transferred electron device.

Reason (R): A Gunn oscillator uses the phenomenon of transferred electron effect.

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Q. Atomic and molecular resonance is observed in many substances

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Q. A reflex klystron oscillator is a

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Q. Consider the following applications:

1. TV tuning
2. Active filter
3. Microwave frequency multiplication

In which of above can a varactor diode be used?

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Q. Consider the following statements:

1. Dissipative attenuator has a fixed value of attenuation.
2. Reflective attenuator has a fixed value of attenuation.
3. Both dissipative and reflective attenuators are available only with fixed attenuation.
4. Both dissipative and reflective attenuators are available with either fixed or variable attenuation.

Which of the above are correct?

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Q. Impedance inversion may be obtained with

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Q. Power gain of a multicavity klystron amplifier is

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Q. The expression HZ = C cos(Bx) cos(Ay)yz is for

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Q. Assertion (A): Impedance matching can be done by using stubs.

Reason (R): A double stub is used for impedance matching when frequency of signal varies.

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Q. Read the following statements about TWT

1. It uses thermionic emission.
2. It uses an attenuater.
3. It is inherently a resonant device.
4. It has broad bandwidth.

Which of the above are correct?

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Q. If a line having Z₀ = 300 ∠ 0 W is short circuited at far end, VSWR is

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Q. A klystron amplifier generally uses Pierce gun

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Q. If a short line is terminated in characteristic impedance it behaves as an infinite line.

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Q. Ga As exhibits negative differential mobility

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