Question

Light of wavelength $\lambda$ falls on a metal having work function $\frac{hc}{{\lambda }_0}$. Photoelectric effect will take place only if

• A. $\lambda \ge {\lambda }_0$
• B. $\lambda \ge 2{\lambda }_0$
• C. $\lambda \le {\lambda }_0$
• D. $\lambda =4{\lambda }_0$

Answer 1

The correct option is C $\lambda \le {\lambda }_0$

For photoelectric effect to take place
hcλ≥hcλ0⇒λ≤λ0