Question

On reducing the wavelength of light incident on a metal, the velocity of emitted photoelectrons will become

• A. Zero
• B. Less
• C. More
• D. Remains uchanged

Answer 1

The correct option is C More

The wavelength of light is given as

$\lambda =\frac{c}{\nu }$

And the maximum kinetic energy for the photoelectrons is

$E_{max}=\frac{1}{2}m{v}^2=h\nu -\varphi$

where, m is the mass and v is the velocity of photoelectrons, $\nu$ is the frequency of incident light and $\varphi$ is photoelectric work function of metal.
Hence, If wavelength of light incident on a metal is decreased, its frequency will increase and hence the velocity of photoelectrons will also increase i.e. be more than earlier

So, the answer is option (C).