21. The critical frequency of ‘F’ layer is greater than 30 MHz. A. True B. False Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option B No explanation is given for this question Let's Discuss on Board
22. Which of the following statement regarding waveguides is incorrect? A. At waveguide can be coupled to a coaxial cable B. At frequencies below the cut off value the wave progresses across the waveguide after total reflections C. Waveguides are usually air filled hollow conducting metallic tubes for transmitting UHF and microwaves D. Waveguides can handle large power at UHF and microwaves Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option A No explanation is given for this question Let's Discuss on Board
23. A rectangular waveguide is a A. Rectangular conducting wire to propagate electromagnetic waves B. Hollow rectangular walled room carrying electromagnetic wave C. Hollow rectangular conducting tube through which electromagnetic waves can be propagat-ed D. Tube antenna to transmit and receive electromagnetic waves Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option C No explanation is given for this question Let's Discuss on Board
24. Tropospheric scatter is used with frequencies in the A. HF B. VHF C. UHF D. VLF Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option C No explanation is given for this question Let's Discuss on Board
25. A Yagi antenna has a driven antenna A. Only B. With a reflector C. With one or more directors D. With a reflector and one or more directors Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option D No explanation is given for this question Let's Discuss on Board
