The collector plate in an experiment on photoelectric effect is kept vertically above the emitter plate . Light source is put on and a saturation photo current is recorded . An electric field is switched on which has a vertically downward direction . Then

Options

A. the stopping potential will decreases
B. the threshold wavelength will increase
C. the photoelectric current will increases
D. the kinetic energy of the current will increases

Answer

d

Explanation

When an electric field is acting vertically downwards, the photoelectron being negatively charged will experience force due to electric field acting vertically upwards, which is the initial direction motion of emitted photoelectrons. Due to it, the electron gets acceleration and hence its K.E. increases