In a historical experiment to determine Planck’s constant, a metal surface was irradiated with light of different wavelengths. The emitted photo electron energies were measured by applying a stopping potential. The relevant data for the wavelength ($$\lambda$$) of incident light and the corresponding stopping potential ($$V_0$$) are given below :

Given that $$c = 3 \times 10^8 ms^{-1}$$ and $$e = 1.6 \times 10^{-19} C$$, Planck’s constant (in units of J s) found from such an experiment is