Question

A photon of wavelength 3000 A strikes a metal surface. The work function of the metal is 2.13 eV. What is the kinetic energy of the emitted photoelectron?

• A. 4.0 eV
• B. 3.0 eV
• C. 2.0 eV
• D. 1.0 eV

Hint:

To calculate the kinetic energy, first compute the energy of the incoming photon and subtract the work function of the metal.

Answer 1

The Correct Option is C

Using the photoelectric equation: $$ E_k = h \nu - W $$ where $E_k$ is the kinetic energy of the emitted photoelectron, $h \nu$ is the energy of the incident photon, and $W$ is the work function. Given, - $h = 6.626 \times 10^{-34} \ \text{Js}$ - $\nu = \frac{c}{\lambda} = \frac{3 \times 10^{8}}{3000 \times 10^{-10}} = 10^{14} \ \text{Hz}$ - $W = 2.13 \ \text{eV}$ Thus, the energy of the photon is: $$ E_k = (6.626 \times 10^{-34} \times 10^{14} - 2.13) \ \text{eV} = 2.0 \ \text{eV} $$