A light ray in air hits piece of quartz at a 39.0 deg angle. Inside the quartz, the light slows down to 2.06*10^8 m/s. At what angle does the light travel in the quarts? (Hint: find n.)
(Unit=deg)

Air is contained in a variable-load piston-cylinder device equipped with a paddle wheel. initially, air is at 400 kpa and 17°c. the paddle wheel is now turned by an external electric motor until 75 kj/kg of work has been transferred to air. during this process, heat is transferred to maintain a constant air temperature while allowing the gas volume to triple. calculate the required amount of heat transfer in kj/kg.