You want to get an idea of the magnitude of magnetic fields produced by overhead powerlines. you estimate the that a transmission wire is about 11m above the ground. the local power company tells you that the lines operate at 240 kv and and provide a maximum power of 46 mw.
a. estimate the magnetic field you might experience walking under one such power line.
b. compare this field to the earth's field: bwire/bearth= ? %

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)