Question

The work functions of some metals are listed below. The metal which will show photoelectric effect when a light of 300 nm wavelength falls on the metal is:

Metal	Work function
Li	2.4
Na	2.3
K	2.2

• A. Li
• B. Na
• C. K
• D. All of the above

Answer 1

The correct option is D All of the above

Energy associated with incident photon $=\frac{hc}{\lambda }E=\frac{6.6\times {10}^{-34}\times 3\times {10}^8}{300\times {10}^{-9}}J=\frac{6.6\times {10}^{-34}\times 3\times {10}^8}{300\times {10}^{-9}\times 1.6\times {10}^{-19}}eV=4.14eV$
Photoelectric effect can effect can take place only when $E_{photon}>\varphi$.
Thus, all the metals given show photoelectric effect