A photocell is operating in saturation mode with a photocurrent 4.8 mA when a monochromatic radiation of wavelength 3000A˚ and power of 1 mW is incident. When another monochromatic radiation of wavelength 1650A˚ and power 5 mW is incident, it is observed that maximum velocity of photoelectron increases to two times. Assuming efficiency of photoelectron generation per incident photon to be same for both the cases, calculate
a. the threshold wavelength for the cell
b. the saturation current in second case
c. the efficiency of photoelectron generation per incident photon