Dual Nature of Radiation and Matter - Result Question 39
41. 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:
«««< HEAD
======= ####41. 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:
c3eec34ec6b1fad69db54a20ad4b2dca40c2aa54 (a) $2.4 V$
(b) $-1.2 V$
(c) $-2.4 V$
(d) $1.2 V$
[2010]
Show Answer
Answer:
Correct Answer: 41. (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 $=-1.2 V$
