Question

The ejection of photoelectrons from the silver metal when the radiation 256.7 nm is used in the photoelectric effect experiment can be stopped by applying the voltage of 0.35V. Calculate the work function for silver metal.

• A. 3.25 eV
• B. 6.26 eV
• C. 4.48 eV
• D. 7.18 eV

Answer 1

The correct option is C 4.48 eV

work function = Energy of incident radiation - K.E of photoelectrons.

$E=\frac{hc}{\lambda }=\frac{(6.626\times {10}^{-34})\times (3.0\times {10}^8)}{256.7\times {10}^{-9}}=7.74\times {10}^{-19}J=4.83eV$

(J to eV can be converted by multiplying the energy value by 6.242e+18)

K.E of the electron = 0.35ev

$\therefore$ work function = $4.83ev-0.35ev=4.48eV$

Hence, the correct option is $C$