Dual Nature Of Light Question 265
Question: Assuming photoemission to take place, the factor by which the maximum velocity of the emitted photoelectrons changes when the wavelength of the incident radiation is increased four times, is [Haryana CEE 1996]
Options:
A) 4
B) $ \frac{1}{4} $
C) 2
D) $ \frac{1}{2} $
Show Answer
Answer:
Correct Answer: D
Solution:
$ \frac{hc}{\lambda }=W_{0}+\frac{1}{2}mv_{\max }^{2} $ Assuming $ W_{0} $ to be negligible in comparison to $ \frac{hv}{\lambda } $ i.e. $ v_{\max }^{2}\propto \frac{1}{\lambda }\Rightarrow {v_{\max }}\propto \frac{1}{\sqrt{\lambda }} $ . (On increasing wavelength l to 4l, vmax becomes half).
BETA
