Q. In microwave system the function of mode filter is

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Q. The total field developed by an antenna array at a distant point is

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Q. High speed logic circuits use

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Q. Which one of the following is transferred locking electron device C antenna?

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Q. A magnetron requires an external magnetic field with flux lines parallel to axis of cathode

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Q. When a line short circuited at far end, the minimum voltage occurs at

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Q. In a TWT the axial component of electric field advances along the tube

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Q. If other parameter are constant, transmission loss at 5 GHz as compared to that at 0.5 GHz is

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Q. For a circular wave guide

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Q. Assertion (A): A half wavelength line can be used as a 1 : 1 transformer.

Reason (R): The input impedance of a half wavelength line is equal to load impedance.

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Q. The magnitudes of OC and SC input impedances of a transmission line an 100 Ω and 25 Ω. The characteristic impedance is

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Q. A loss less line is terminated in a circular lines are E lines

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Q. A coaxial line has L = 500 nH/m and C = 50 pF/m. The characteristic impedance is

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Q. The main feature of a parametric amplifier is

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Q. Assertion (A): PIN diode is commonly used for microwave control.

Reason (R): A PIN diode uses heavily doped p and n materials.

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Q. In a vacuum tube, the transit time of electron between cathode and anode is important at

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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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