Question

Photons of energy 6 eV are incident on a metal surface whose work function is 4 eV. The minimum kinetic energy of the emitted photo-electrons will be

• A. 0 eV
• B. 1 eV
• C. 2 eV
• D. 10 eV

Answer 1

Answer: (A)

Step 1, Given data

Energy of photon = 6 eV

Work function = 4 eV

Step 2, Finding the minimum energy of the emitted electron

We know,

Work function is the minimum energy that is required to make the electron come out of the surface.

So,

The energy of the emitted electron = Energy of the photon - Work function

So, Energy of the emitted electron = 6 eV - 4 eV = 2 eV

Hence the minimum energy of the emitted electron is 2 eV.