Dual Nature Of Light Question 290
Question: The work functions for sodium and copper are $ 2eV $ and $ 4eV $ . Which of them is suitable for a photocell with 4000 Å light [RPET 1999]
Options:
A) Copper
B) Sodium
C) Both
D) Neither of them
Show Answer
Answer:
Correct Answer: B
Solution:
Threshold wavelength for Na, $ {\lambda_{Na}}=\frac{12375}{2}=6187.5{\AA} $ Also $ {\lambda_{Cu}}=\frac{12375}{4}=3093.75 $ Since $ {\lambda_{Na}}>4000{\AA} $ ; So Na is suitable.
BETA
