Question

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

• A. None
• B. A only
• C. A and B only
• D. All the three metals

Answer 1

The correct option is C A and B only

Energy of electron with an associated wavelength of $4100A^{\circ }$ is:

$\Rightarrow \frac{hc}{\lambda }=4.845\times {10}^{-19}J$

$=3.024eV$

This incident electron would emit photon from metals whose work potential is less than its energy.

Thus, it would emit photons from metals A and B.