Question 377: Dual Nature of Matter and Radiation

Question

When photons of energy $h v$ fall on a metal plate of work function ' $W_0$ ', 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

Accepted Answer

Given, energy of photon $=h 
u$, work function $=W_0$ and maximum kinetic energy $=K$
So, from the Einstein's photoelectric equation,
$$\begin{aligned}
& E=K+W_0 \Rightarrow h v=K+W_0 \
& \Rightarrow \quad K=h v-W_0\quad 	ext{... (i)}
\end{aligned}$$
If frequency of the radiation is doubled, then Einstein's photoelectric equation changed as
$$K^{\prime}=h(2 v)-W_0\quad 	ext{... (ii)}$$
By substracting the Eq. (i) from (ii), we get
$$\begin{aligned}
K^{\prime}-K & =h(2 v)-h v-W_0+W_0 \
\Rightarrow \quad K^{\prime} & =K+h v
\end{aligned}$$
So, option (b) is correct.

Answer

$K+W_0$

Answer

$K+h v$

Answer

$\mathrm{K}$

Answer

$\mathrm{2 K}$

Dual Nature of Matter and Radiation

When photons of energy h v fall on a metal plate of work function ' W_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

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