Dual Nature Of Radiation And Matter Ques 37
37. The potential difference that must be applied to stop the fastest photoelectrons emitted by a nickel surface, having work function $5.01$ $ eV$, when ultraviolet light of $200$ $ nm$ falls on it, must be:
[2010]
(a) $2.4 $ $V$
(b) $-1.2 $ $V$
(c) $-2.4 $ $V$
(d) $1.2 $ $V$
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Answer:
Correct Answer: 37.(b)
Solution:
- (b) $K _{\max }=\frac{h c}{\lambda}-W=\frac{h c}{\lambda}-5.01$
$=\frac{12375}{\lambda(\text{ in } \AA)}-5.01$
$=\frac{12375}{2000}-5.01=6.1875-5.01=1.17775$
$\simeq 1.2 $ $V$
The potential difference that must be applied to stop photoelectrons $=-1.2$ $ V$
BETA
