NEET-XII-Physics
neet 2020 questions with solutions year:2020
- #22Light of frequency 1.5 times the threshold frequency is incident on a photosensitive material. What will be the photoelectric current if the frequency is halved and intensity is doubled?
(A)doubled
(B)four times
(C)one-fourth
(D)zero
digAnsr: DAns : `` K_{1}=1.5 \,hv_{0}-\phi_{0}=0.5\,hv_{0} ``
`` K_{2}=\frac{1.5}{2}hv_{0}-hv_{0}=-0.25\,hv_{0} ``
`` \because `` Kinetic energy can never be negative, so no emission and `` i=0 ``