Dual Nature Of Radiation And Matter Ques 45
45. When photons of energy $h v$ fall on an aluminium plate (of work function $E_0$ ), photoelectrons of maximum kinetic energy $K$ are ejected. If the frequency of the radiation is doubled, the maximum kinetic energy of the ejected photoelectrons will be
[2006]
(a) $2 K$
$K$
(c) $K + h v$
(d) $K+E_0$
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Answer:
Correct Answer: 45.(c)
Solution:
- (c) Applying Einstein’s formula for photoelectricity
$h v=\phi+\frac{1}{2} m v^{2} ; \quad h v=\phi+K_{\text{max}}$
$\phi=h v - W_0$
If we use $2v$ frequency then let the kinetic energy becomes $K^{\prime}$
So, $h \cdot 2v=\phi+K$
$2 h v=h v-K+K^{\prime}$
$K^{\prime}=h v+K_{0}$
BETA
