Dual Nature Of Radiation And Matter Ques 54
54. The photoelectric work function for a metal surface is $4.125$ $ eV$. The cut off wavelength for this surface is
[1999]
(a) $4125 $ $\AA$
(b) $3000 $ $\AA$
(c) $6000 $ $\AA$
(d) $2062.5 $ $\AA$
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Answer:
Correct Answer: 54.(b)
Solution:
- (b) Let $\lambda_0$ be cut off wavelength.
Work function $=\frac{h c}{\lambda_0}=4.125 \times 1.6 \times 10^{-19}$
$\lambda_0=\frac{6.626 \times 10^{-34} \times 3 \times 10^{8}}{4.125 \times 1.6 \times 10^{-19}}=3000 $ $\AA$
BETA
