Question

The work functions for metals A,B and C are respectively 1.92 eV, 2.0 eV and 5 eV. According to Einstein's equation, the metals which will emit photoelectrons for a radiation of wavelength 4100 Å is/are:

• A. none
• B. A only
• C. A and B only
• D. all the three metals

Answer 1

Answer: (C)

A and B only

Answer 2

Energy of electron with wavelength of 4100A° is
$\frac{hc}{\lambda}$ = 4.845x10-19J
= 3.024eV
This incident electron would emit photon from metals whose work potential is less than its energy.
so, it would emit photons from metals A and B.

Therefore, the correct option is (C): A and B only