Question
Light of wavelength $\lambda$ falls on a metal having work function $\frac{\text{h}_\text{c}}{\lambda_0}.$ Photoelectric effect will take place only if:
- $\lambda\geq\lambda_0$
- $\lambda\geq2\lambda_0$
- $\lambda\leq\lambda_0$
- $\lambda<\frac{\lambda_ 0}{2}.$