2. Assertion (A): TWT uses a focussing mechanism to prevent the electron beam from spreading.Reason (R): In a TWT the electron beam has to travel a much longer distance than in klystron.
3. In a TWT the amplitude of resultant wave travelling down the helix
4. Which of the following is not a travelling wave?
5. Both Impatt and Trapatt devices use avalanche effect
6. In a directional coupler
7. As the frequency is increased, the charging MVAR in a cable
8. Loss angle of a good quality cable is about
9. In a three cavity klystron amplifier, the oscillations are excited in
10. In the given figure reflection coefficient at load is
11. Which of the following lines is non-radiating?
12. 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.
13. Skin effect is more pronounced at high frequencies.
14. Assertion (A): The phenomenon of differential mobility is called transferred electron effect.Reason (R): GaAs exhibits transferred electron effect.
15. Which of the following devices uses a helix?
16. Which of the following parameters is negligible in transmission lines?
17. The width of a radio beam from a 1 m diameter parabolic antenna at 10 GHz is about
18. The diagram to show distance time history of electrons in klystron amplifier is called
19. Impedance level of Impatt diodes is generally lower than that of Gunn diodes
20. A quarter wave line open circuited at far end behaves as
21. A line has Z0 = 300 ∠ 0° Ω. If ZL = 150 ∠ 0° Ω, reflection coefficient is
22. Assertion (A): A backward wave oscillator has an internal positive feedback.Reason (R): A positive feedback is necessary for sustained oscillations.
23. In a microstrip transmission the signal can be easily redirected by changing the centre strip.
24. The frequency of oscillation in a backward wave oscillator can be changed by
25. A line has a phase constant of 29.8 rad/m. At 1000 MHz the wavelength is