Question

If the wavelength of light in an experiment on photo electric effect is doubled

• A. the photoelectric emission will not take place.
• B. the photoemission may or may not take place
• C. the stopping potential will increase
• D. the stopping potential will decrease under the condition that energy of photon of doubled wavelength is more than work function of metal

Answer 1

Answer: (B), (D)

The correct options are
B the photoemission may or may not take place
D the stopping potential will decrease under the condition that energy of photon of doubled wavelength is more than work function of metal

Photo-electric emission is possible if $\lambda <{\lambda }_0$ where ${\lambda }_0$ is threshold wavelength

$\frac{hc}{\lambda }=e|V_s|+\varphi$

As $\lambda$ increases, $V_s$ decreases