Question

The threshold wavelength for emission of photoelectrons from a metal surface is $6\times {10}^{-7}$m. The work function of the material of the metal surface is :

• A. $3.33\times {10}^{-19}J$
• B. $6.67\times {10}^{-19}J$
• C. $1.23\times {10}^{-19}J$
• D. $2.37\times {10}^{-19}J$

Answer 1

The correct option is A $3.33\times {10}^{-19}J$

Threshold wavelength of the photoelectrons $\lambda =6\times {10}^{-7}m=600nm$

Work function of the material is given by $\varphi =\frac{hc}{\lambda }$

$\varphi =\frac{1240}{600}\times 1.6\times {10}^{-19}$ where $(hc=1240ev-nm)$

$\varphi =3.33\times {10}^{-19}J.$
So, the answer is (A).