Question

The maximum wavelength that an electromagnetic wave can have and still eject electrons from a metal surface is 459 nm. What is the work function W0 of this metal? Express your answer in electron volts.

Answer 1

Data:

Threshold wavelength, λo = 459 nm

                                        = 459 x 10^-9 m

Solution:

Work function, Wo = h c / λo

                               = 6.6 x 10^-34 * 3 x 10^8 / 459 x 10^-9

                                = 4.314 x 10^-19 J

                                = ( 4.314 x 10^-19 / 1.6 x 10^-19 ) eV

                                = 2.7 eV

Ans:

Work function, Wo = 2.7 eV