In a photoelectric experiment, the collector plate is at 2.0V with respect to the emitter plate made of copper (ϕ=4.5eV). the emitter is illuminated by a source of monochromatic light of wavelength 200 nm.
K=hcα−ϕ
=6.63×10−34×3×108200×10−9×1.6×10−19−4.5
=1.7eV
Min. energy with which electrons emitted=1.7eV
Max. Kε⇒Kmin+eV0
=1.7+2
=3.7eV