The electric-field phasor of a uniform plane wave traveling downward in water is given by where is the downward direction and is the water surface. If , Find the impedance. Obtain an expression for the average power density. Determine the depth at which the power density has been reduced to of the initial value.

Refrigerant-134a flows through a carnot heat pump cycle at 0.5 kg/s. it is known that the maximum absolute temperature in the cycle is 1.1 times the minimum absolute temperature, and the net power input to the cycle is 2.5 kw. if the refrigerant changes from a saturated vapor to a saturated liquid during the heat rejection process, determine the maximum magnitude of the enthalpy of vaporization for this process in kj/kg (with 3 significant figures).