Density of hvdrogen at T-0C temperature and atmospheric pressure is ?,-0.0000896 gr/cm3 and index of refraction n-1.000138. Density of liquefied hydrogen is pz-0.068 gr/cm3. Given that Lorenz-Lorentz formula is valid for this case (formula that relates index of refraction and atomic parameters for solid-state case, in Hecht's book formula #3.74) find index of refraction of liquefied hydrogen.

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).