## Question

Light of wavelength 3500 Å is incident on two metals *A* and *B*. Which metal will emit photoelectrons, if their work functions are 4.2 eV and 1.9 eV respectively?

### Solution

Metal B, 3.54 eV

The energy of incident light photon of wavelength

is

= 3.54 eV.

The incident light will yield photoelectrons if its energy is greater than the work function of the metal. Thus, metal B(W = 1.9 eV) will emit photoelectrons.

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