In the military, night vision goggles are used to pull off secret missions into areas that are very dangerous. for this reason, the soldiers try to infiltrate at night so they can't be seen. thermal-imaging devices are often used as well to locate people on these highly secretive missions. what type of electromagnetic radiation is being utilized?

Arefrigerator uses r-134a as the working fluid and operates on the ideal vapor-compression refrigeration cycle except for the compression process. the refrigerant enters the evaporator at 120 kpa with a quality of 34 percent and leaves the compressor at 70°c. if the compressor consumes 450 w of power, determine (a) the mass flow rate of the refrigerant, (b) the condenser pressure, and (c) the cop of the refrigerator. (0.00644 kg/s, 800 kpa, 2.03)