SOLVED

11.In a radar system, which of the following are frequently detected when there is a large target close by? A. Double range echoes B. Second return echoes C.Multiple-time around echoes D. Duty cycles 12.Cavity resonators are metal-walled chambers fitted with devices for admitting and extracting what type of energy? A. RF B.Electromagnetic C. Magnetic field D. Microwave 13.How many feet is the nautical mile, which is the accepted unit of distance in radar? A.6076 ft. B.6000 ft. C.5280 ft. D.2000 ft. 14. Which of the following would be a use of a variable attenuator at microwave frequencies? A. To prevent reflections B. To change the physical direction of propagation C. To measure signal levels D. To change the plane of polarization ofthe wave 15.Transmission lines, antennas, and fiber optics are the commonly known meansof _______________. A.information-carrying capacity B.high-frequency transmission C.low-frequency transmission D.electromagnetic waves 16.Like coaxial lines, waveguides are perfectly shielded, which allows for no _____________. A. radiation loss B. power loss C. energy loss D. noise 17.Which of the following is the most dominant mode of operation because it is the most “natural”one for operation? A. RG-52/U B. TE10 C. GHz D. TM 18.What one unique advantage do ridged waveguides provide? A. It consists of a main run with a rectangularwaveguide and a circular rotating joint. B. It is less expensiveto manufacture than a standard rectangular waveguide. C. It allows operation at lower frequencies for a given set of outside dimensions. D. It has a value greater than the speed oflight. 19.Why is a waveguide often pressurized with nitrogen? A.Toprevent contamination B.To change the plane of polarization ofthe wave C.To attach or weld a metal plate at the endof the waveguide D.To prevent reflections 20.It is often necessary to change the physical direction of propagation or the wave’s polarizationin waveguides. What is the purpose of a twist section? A. To produce shuntingreactance across the guide B. To change the plane of polarization ofthe wave C. To change the physical directionof propagation D. So low received power does no damage to the powerfultransmitter output