Acertain part of the electromagnetic spectrum ranges from 200 nm to 400 nm. what is the lowest frequency associated with this portion of the spectrum? (c 3.00 108 m/s)

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.