Question

In a photoelectric experiment for 4000 Å incident radiation, the potential difference to stop the ejection is 2 V. If the incident light is changed to 3000 Å, then the potential required to stop the ejection of electrons will be

• A. 2 V
• B. Less than 2 V
• C. Zero
• D. Greater than 2 V

Answer 1

The correct option is D Greater than 2 V

According to Einstein's photoelectric equation $E=W_0+K_{max}\Rightarrow V_0=\frac{hc}{e}[\frac{1}{\lambda }-\frac{1}{{\lambda }_0}]$
Hence if $\lambda$ decreases $V_0$ increases.