Value of work function \( (W_0) \) for a few metals are given below:
The number of metals which will show photoelectric effect when light of wavelength is \( 400 \, \mathrm{nm} \) falls on it is _____.
Given \( h = 6.6 \times 10^{-34} \, \mathrm{J\,s} \)
\( c = 3 \times 10^{8} \, \mathrm{m\,s^{-1}} \)
\( e = 1.6 \times 10^{-19} \, \mathrm{C} \)
