Some devices use electromagnetic waves to find the location and speed of an object. In these devices, the waves are emitted and then reflected off of the object and returned back toward the device. By knowing the speed of the wave and the time it takes the wave to return to the device, the distance that the wave traveled can be calculated. Which type of wave would be safest to use in this type of device?

4r-134a enters the condenser of a residential heat pump at 800 kpa and 50°c at a rate of 0.022 kg/s and leaves at 750 kpa subcooled by 3°c. the refrigerant enters the compressor at 200 kpa superheated by 4°c determine (a) the isentropic efficiency of the compressor, (b) the rate of heat supplied to the heated room, and (c) the cop of the heat pump. also, determine (d) the cop and rate of heat supplied to the heated room if this heat pump operated on the ideal vapor-compression cycle between the pressure limits of 200 and 800 kpa. (0.757, 4.37 kw, 5.12, 6.18, 3.91 kw)