Question

The velocity of the photoelectron (\(in~ms^{-1}\)) emitted when a smooth surface of a metal is made to strike with a photon of wavelength \(4\times10^{-7}m\) (\(W_{0}\) of metal \(=2.13~eV\); \(1eV=1.6\times10^{-19}J\); \(h=6.6\times10^{-34}Js\); \(m_{e}=9.1\times10^{-31}kg\))

• A. \(\frac{1}{\sqrt{5}}\times10^{6}\)
• B. \(\frac{1}{\sqrt{3}}\times10^{5}\)
• C. \(\frac{1}{\sqrt{3}}\times10^{6}\)
• D. \(\frac{1}{\sqrt{7}}\times10^{5}\) \bigskip

Hint:

For photoelectric effect: \[ K_{\max}=\frac{hc}{\lambda}-W_0 \] and \[ v=\sqrt{\frac{2K_{\max}}{m}} \] Always convert eV into joules before calculating velocity.

Answer 1

The Correct Option is C