MHT CET 2017 Physics Solved Paper

(b) According to the Einstein’s photoelectric equation,
KEmax = hv0−ϕ0
Initially, hv = 0.4 + ϕ0 ...(i)
and when the frequency of incident radiation is increased by 30% then
1.3 hv = 0.9 + ϕ0 ...(ii)
From eqs. (i) and (ii)
0.3 ϕ0 = 0.9 - 1.3(0.4)
∴ ϕ0 =

0.38

0.3

= 1.267 eV