Dual Nature Of Light Question 96
Question: Light from a hydrogen discharge tube is incident on the cathode of a photoelectric cell the work function of the cathode surface is 4.2 eV. In order to reduce the photo-current to zero the voltage of the anode relative to the cathode must be made [DCE 2002]
Options:
A) ? 4.2 V
B) ? 9.4 V
C) ? 17.8 V
D) +9.4 V
Show Answer
Answer:
Correct Answer: B
Solution:
$ E=W_{0}+eV_{0} $ For hydrogen atom, $ E=+13.6,eV $ \ + 13.6 = 4.2 + eV0
Þ $ V_{0}=\frac{(13.6-4.2),eV}{e}=9.4,V $ Potential at anode = ? 9.4 V
BETA
