Dual Nature Of Radiation And Matter Ques 2
2. Light of frequency $1.5$ times the threshold frequency is incident on a photosensitive material. What will be the photoelectric current if the frequency is halved and intensity is doubled?
[2020]
(a) four times
(b) one-fourth
(c) zero
(d) doubled
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Answer:
Correct Answer: 2.(c)
Solution: (c) For photoelectric emission, photoelectric current, incident light frequency should be greater than threshold frequency.
Light of frequency $1.5$ times the threshold frequency $v_0$ incident.
$ v=\frac{3}{2} v_0 $
If frequency is halved,
$ \begin{aligned} & \therefore v^{\prime}=\frac{v}{2}=\frac{3}{4} v_0 \\ & \because v^{\prime}<v_0 \end{aligned} $
$\therefore$ No photoelectric emission will take place.
BETA
