Question

The energy required to overcome the attractive forces on the electrons, w, of some metals is listed below . The number of metals showing photoelectric effect when light of 300 nm wavelength falls on it is :

Answer 1

Hello there
The energy of a 300 nm light can be calculated by the formula
E=hc/λ
or,E=1242/300 eV
or,E=4.14 eV
Now compare this energy with that of different metals which are listed,the metals having energy less than 4.14 eV will show photoelectric effect.

Cheers!