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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Q. Consider the following statements:

1. Bunching of electrons occurs in two cavity klystron amplifier.
2. Bunching of electrons occurs in multi cavity klystron amplifier.
3. Bunching of electrons occurs in reflex cavity klystron amplifier.

Which of the above statements are correct?

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Q. Assertion (A): For high frequency lines inductive reactance is very high as compared to ac resistance.

Reason (R): Due to skin effect ac resistance of line is higher than dc resistance.

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Q. Consider the following applications

1. Switch
2. Attenuator
3. Phase shifter
4. Oscillator

In which of the above can a PIN diode be used?

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Q. Out of modes TE₂₀ and TE₃₀ of propagation of electromagnetic engery

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Q. A TE₁₀ rectangular waveguide is to be designed for operation over 25-35 GHz and the band centre is 1.5 times the cutoff frequency. The dimension of broadside is

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Q. In a klystron amplifier the force on all electrons

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Q. If load impedance ZL >> Z0, then

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Q. The inductance of a twin feeder used to connect antenna to TV receiver is about

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Q. Assertion (A): Impatt diode is an avalanche diode.

Reason (R): Avalanche breakdown phenomenon occurs when a p-n junction is reverse biased.

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Q. A radar has a maximum range of 120 km. The maximum allowable pulse repetition frequency for unambiguous reception is

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Q. In a line with finite attenuation

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Q. The electric field in a TWT due to applied signal

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Q. A 75 ohm line is first short terminated and minima locations are noted. Then the short is replaced by resistive load and minima location are again noted. If minima location are not altered and VSWR is 3, the value of resistive load is

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Q. The word 'LORAN' means

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