Question

The work function for photoelectric effect

• A. Is same for all metals
• B. Is different for different metals
• C. Depends upon the intensity of incident light
• D. Depends upon the frequency of incident light

Answer 1

Answer: (B)

In solid-state physics, the work function (sometimes spelled workfunction) is the minimum thermodynamic work (i.e. energy) needed to remove an electron from a solid to a point in the vacuum immediately outside the solid surface.
The work function is not a characteristic of a bulk material, but rather a property of the surface of the material (depending on crystal face and contamination), and varies for different metals.
The work function of some metals is given below as an eg,

Element	Work Function(eV)
Aluminum	4.08
Beryllium	5.0
Cadmium	4.07
Calcium	2.9
Carbon	4.81
Cesium	2.1
Cobalt	5.0
Copper	4.7
Gold	5.1
Iron	4.5
Lead	4.14
Magnesium	3.68
Mercury	4.5
Nickel	5.01
Niobium	4.3
Potassium	2.3
Platinum	6.35
Selenium	5.11
Silver	4.26-4.73*
Sodium	2.28
Uranium	3.6
Zinc	4.3