Q. Consider the following statements about directional coupler shown in the figure:

1. Ports 1 and 2 are decouple
2. Ports 3 and 4 are decoupled
3. Pots 1 and 3 are decoupled
4. Ports 1 and 4 are decoupled

Which of the above statements are correct?

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Q. Two identical hybrid tees are joined as shown in the given figure. If 16 mW power is fed into port 1, the power output at ports 2 , 3, 1', 2', 3' respectively is

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Q. If QL is loaded Q, QE is external Q and QU is unloaded Q of a microwave resonator, then

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Q. Which of the following lines is non-radiating?

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Q. Assertion (A): The impedance of a matched load is equal to characteristic impedance of line.

Reason (R): A matched termination absorbs all the power incident on it.

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Q. Skin effect is more pronounced at high frequencies.

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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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