Question

The emission of photo electrons in the process of photo electric effect is

• A. Due to increase in temperature of photo metal
• B. Due to incidence of photons of proper wavelength
• C. Due to incidence of photons of proper velocity
• D. Due to incidence of photons of proper intencity

Answer 1

Answer: (B)

Due to incidence of photons of proper wavelength

$hv=h{v}_0+K.E$

$\Rightarrow \frac{hc}{\lambda }=\frac{hc}{{\lambda }_0}+K.E.$

Only for $\lambda <{\lambda }_0,$ electrons are emitted.