The collector plate in an experiment on photo electric effect is kept vertically above the emitter plate.  Light source is put on and a saturation photo current is recorded. Parallel electric and magnetic fields are applied vertically downwards between the plates. Then

emitted photo-electrons moves upwards, when electric and magnetic fields are applied in vertically downward direction, no magnetic force acts and but electric force acts opposite to electric field i.e. upwards , hence electrons reach collector plate with grater velocity, 

hence Its kinetic energy increases, also stopping potential increases   

As intensity of radiation does not changed, photo-electric current does not changes