43. For handling high powers, it is best to use
A. rectangular waveguide
B. stripline
C. coaxial cable
D. microstrip

---

44. The cavity magnetron employs strapping in order to
A. prevent mode jumping
B. reduce frequency pushing and pulling
C. ensure bunching
D. permit better dissipation of heat

---

45. Indicate the FALSE statement :Frequency-agile or dither-tuned magnetron
A. has a movable piston for changing its operating frequency
B. can be easily jammed
C. may be conventional or coaxial
D. is capable of sending a series of pulses each of which is at a different frequency

---

46. Which statement regarding voltage tunable magnetrons (VTMs) is wrong?
A. they use high-Q cavities
B. they have an extra injection electrode to help bunching
C. their operating frequency can be varied over an octave by adjusting anode votage
D. they use cold cathodes

---

47. The cut-off frequency in a waveguide means
A. longer waves will not propagate significantly
B. determine the dimensions of waveguide
C. frequency at which no transmission takes place.
D. None of above

---

48. For a standard X-band waveguide of cross-sectional dimension 2.286 cm x 1.016 cm, the cut-off wavelength for a TEio mode is ___ cm.
A.2.286
B.2.032
C.4.572
D.3.02

---

49.  The signal delay caused when a wave travels a distance Z metres through a hollow wave guide is where VPh' V and Vo represent phase gr velocity, group velocity and free space velocity (m/sec) respectively. given by
A. Z/Vph
B.ZN
C.Z/Vo
D. ZN'.V

---