We shine light of three different wavelengths—333 nm, 430 nm, and 649 nm—on a metal surface. the observations for each wavelength, labeled a, b, and c, are: observation a: no photoelectrons are observed. observation b: photoelectrons with a kinetic energy of 159 kj/mol are observed observation c: photoelectrons with a kinetic energy of 48 kj/mol are observed

Air initially at 0.75 bar, 1000 k, and occupying a volume of 0.12 m^3 undergoes two processes. process 1-2: the air is compressed isothermally until the volume is halved. process 2-3: the air undergoes a constant pressure process until the volume is halved again. assume ideal gas behavior. a) determine the mass of the air, in kg. b) the work and the heat transfer for each of the two processes, in kj. (100 kj = 1 bar . m^3)