Question

The given figure shows few data points in a photo electric effect experiment for a certain metal. The minimum energy for ejection of electrons from its surfaces :(Planck's constant $h=6.62\times {10}^{-34}\text{Js}$)

• A. $\text{2.27 eV}$
• B. $\text{2.59 eV}$
• C. $\text{1.93 eV}$
• D. $\text{2.10 eV}$

Answer 1

The correct option is A $\text{2.27 eV}$

From the given graph at $\text{B}(5.5\times {10}^{14}\text{Hz},0\text{eV})$

From, Einstein's photoelectric equation,

$h\nu =\varphi +e{V}_0$
$\text{Minimum energy for ejection of electron = Work function}\left(\varphi \right)$
$\varphi =h\nu \text{J}$
$\varphi =\frac{h\nu }{e}\text{eV}(\text{for}{V}_s=0)$
$\therefore \varphi =\frac{6.62\times {10}^{-34}\times 5.5\times {10}^{14}}{1.6\times {10}^{-19}}=2.27\text{eV}$

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> Hence, $\left(A\right)$ is the correct answer.