Two radiations of photons energies 1 eV and 2.5 eV, successively

Two radiations of photons energies 1 eV and 2.5 eV, successively illuminate a photosensitive metallic surface of work function 0.5 eV. The ratio of the maximum speeds of the emitted electrons is :

According to Einsten’s photoelectric effect, the K.E. of the radiated electrons
K.E_max = E – W

	1	mv²₁
	2

= (1 – 0.5) eV = 0.5 eV

	1	mv²₂
	2

= (2.5 – 0.5) eV = 2 eV