The action of backward wave oscillator is similar to that of klystron amplifier

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Correct Answer

TWT

Explanation

It is somewhat similar to TWT and can deliver microwave power over a wide frequency band.

It has an electron gun and a helix structure. However the interaction between electron beam and RF wave is different than in TWT.

The growing RF wave travels in opposite direction to the electron beam.

The frequency of wave can be changed by changing the voltage which controls the beam velocity.

Moreover the amplitude of oscillations can be decreased continuously to zero by changing the beam current.

It features are:

1. Frequency range - 1 GHz to 1000 GHz.

2. Power output - 10 mV to 150 mW (continuous wave) 250kW (pulsed).

It is used as signal source in transmitters and instruments.

2. A loss less line of characteristic impedance Z₀ is terminated in pure reactance of -jZ₀ value. VSWR is
Options
A. 10
B. 2
C. 1
D. infinity

3. 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.
Options
A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is correct but R is wrong
D. A is wrong but R is correct

4. In a klystron amplifier dc electron velocity is v₀ and dc electron charge density is r₀ the dc beam current is
Options
A. r₀v₀
B. r₀^/v₀
C. v₀^/r₀
D. (v₀^/r₀)²