Q. Assertion (A): The phenomenon of differential mobility is called transferred electron effect.

Reason (R): GaAs exhibits transferred electron effect.

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Q. Which of the following devices uses a helix?

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Q. The action of backward wave oscillator is similar to that of

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Q. Assertion (A): Artificial transmission lines are frequently used in laboratories.

Reason (R): An artificial transmission line can be used to represent an actual line and can also be used as a delay circuit, as attenuator, as filter network etc.

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Q. In a backward wave oscillator the wave travelling along the line winds itself back and forth

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Q. A line is excited by a 100 V dc source. If reflection coefficients at both ends are 1 each then

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Q. A line has Z0 = 300 ∠ 0° Ω. If ZL = 150 ∠ 0° Ω, reflection coefficient is

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Q. Assertion (A): A backward wave oscillator has an internal positive feedback.

Reason (R): A positive feedback is necessary for sustained oscillations.

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Q. In a microstrip transmission the signal can be easily redirected by changing the centre strip.

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Q. The frequency of oscillation in a backward wave oscillator can be changed by

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Q. A line has a phase constant of 29.8 rad/m. At 1000 MHz the wavelength is

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Q. In a directional coupler

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Q. As the frequency is increased, the charging MVAR in a cable

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Q. Loss angle of a good quality cable is about

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Q. In a three cavity klystron amplifier, the oscillations are excited in

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Q. Assertion (A): A coaxial line is a non-radiating line.

Reason (R): In a coaxial line the electric and magnetic fields are confined to the region between the concentric conductors.

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Q. Reflex klystron oscillator is essentially a low power device

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Q. A 10 km long line has a characteristic impedance of 400 ohms. If line length is 100 km, the characteristic impedance is

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Q. A matched generator (Zg = Z0) with 1 Ω available. If all ports are matched, the power delivered at ports 1, 2, 3 respectively are

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Q. Which TM mode in rectangular waveguide has lowest cutoff frequency?

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