Dual Nature Of Light Question 94
Question: Ultraviolet light of wavelength 300 nm and intensity 1.0 watt/m2 falls on the surface of a photosensitive material. If 1% of the incident photons produce photoelectrons, then the number of photoelectrons emitted from an area of 1.0 cm2 of the surface is nearly [AMU 1995]
Options:
A) $ 9.61\times 10^{14}per\ \sec $ per sec
B) $ 4.12\times 10^{13}per\ \sec $ per sec
C) $ 1.51\times 10^{12}per\ \sec $ per sec
D) $ 2.13\times 10^{11}per\ \sec $ per sec
Show Answer
Answer:
Correct Answer: C
Solution:
Intensity of light $ I=\frac{Watt}{Area}=\frac{nhc}{A\lambda } $
Þ Number of photon $ n=\frac{IA\lambda }{hc} $ \ Number of photo electron = $ \frac{1}{100}\times \frac{IA\lambda }{hc} $ $ =\frac{1}{100}\frac{1\times {{10}^{-4}}\times 300\times {{10}^{-9}}}{6.6\times {{10}^{-34}}\times 3\times 10^{8}}=1.5\times 10^{12} $
BETA
