AP EAMCET Engineering 21 Apr 2019 Shift 1 Paper

The maximum kinetic energy of a photoelectron liberated from the surface of lithium with work function 2.35 eVby electromagnetic radiation whose electric component varies with time as E = a [1 + cos (2πf1t)] cos 2πf2t (where 'a' is a constant) is
(f1 = 3.6 × 1015 Hz , f2 = 1.2 × 1015 Hz and Plank’s constant = 6.6 × 10−34 J-s)