Dual Nature Of Light Question 264
Question: Light of wavelength 4000 Å falls on a photosensitive metal and a negative 2V potential stops the emitted electrons. The work function of the material (in eV) is approximately $ (h=6.6\times {{10}^{-34}}Js,\ \ e=1.6\times {{10}^{-19}}C,\ \ c=3\times 10^{8}m{{s}^{-1}}) $ [MP PMT 1995; MH CET 2004]
Options:
A) 1.1
B) 2.0
C) 2.2
D) 3.1
Show Answer
Answer:
Correct Answer: A
Solution:
Energy of incident light $ E,(eV)=\frac{12375}{4000}=3.09,eV $ Stopping potential is ? 2V so $ {K_{\max }}=2,eV $ Hence by using $ E=W_{0}+{K_{\max }} $ ; W0 $ =1.09,eV $ $ \approx ,1.1,eV $
BETA
