Q. Assertion (A): A line of length λ/4 and short circuited at far end has an input impedance of infinity.

Reason (R): A line of length λ/4 and short circuited at far end behaves as a parallel resonant circuit.

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Q. Assertion (A): PIN diode is used as a fast switch.

Reason (R): PIN diode has very high resistance when reverse biased and very low resistance when forward biased.

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Q. A pulsed radar produces 1 μ sec pulses at a rate of 1000 per second. The duty cycle is

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Q. Assertion (A): Impedance measurement at microwave frequencies is done by finding SWR.

Reason (R): SWR and reflection coefficient depend on the characteristic impedance and load impedance.

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Q. Which device has internal positive feedback?

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Q. A coaxial RF cable has a characteristic impedance of 50 Ω and C equal to 40 pF/m. The inductance is

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Q. In a multicavity klystron amplifier the signal to be amplified develops an ac voltage of signal frequency across the gap in buncher cavity

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Q. If VSWR is infinite, the transmission line is terminated in

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Q. The semiconductor diode which can be used in switching circuit in microwave range is

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Q. A line has an attenuation of 0.054 Np/m. The attenuation in decibels is

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Q. If a line is open circuited Zin = Z0 tanh (gl).

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Q. A reflex klystron oscillator uses

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Q. Which one of the following is not a negative resistance device?

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Q. Microwave links are typically 50 km apart

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Q. For matching over a range of frequencies in a transmission line it is best to use

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Q. Assertion (A): In the interaction region of magnetron an electron is subjected to three forces: force due to electric field, force due to magnetic field and centrifugal force.

Reason (R): The mechanism of generation of microwaves, in a magnetron, involves interaction of electromagnetic fields with electrons moving in static electric and magnetic fields oriented at right angles to each other.

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Q. Which of the following is wrong for a magic used to tee?

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Q. Roughly the time required for microwave cooking as compared to conventional cooking is

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Q. If the minimum range of a radar is to be doubled, the peak power has to be increased by a factor of

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Q. Which mode has the lowest cut off frequency in circular wave guides?

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