In a historical experiment to dtermine Planck's constant, a metal surface was irradiated with light of different wavelengths. The emitted photoelectron energies were measured by applying a stopping potential. The relevant data for wavelength (lamda) of incident light and the corresponding stopping potential (V_(0)) are given below Given that c=3xx10^(8)ms^(-1) and e=1.6xx10^(-19)C, Planck's constant (in units of J s) found from such an experiment is:

In a historical experiment to dtermine Planck's constant, a metal surf

1.	In a historical experiment to dtermine Planck's constant, a metal surface was irradiated with light of different wavelengths. The emitted photoelectron energies were measured by applying a stopping potential. The relevant data for wavelength (lamda) of incident light and the corresponding stopping potential (V_(0)) are given below Given that c=3xx10^(8)ms^(-1) and e=1.6xx10^(-19)C, Planck's constant (in units of J s) found from such an experiment is:
Answer» `6.0xx10^(-34)` `6.4xx10^(-34)` `6.6xx10^(-34)` `6.8xx10^(-34)`. Solution :For photoelectronic emission, `(hc)/(LAMDA)=E_(0)+eV_(0)` . . . .(i) Here, kinetic ENERGY of photoelectron `((1)/(2)mv^(2))=eV_(0)` `(hxx3xx10^(8))/(0.4xx10^(-6))=E_(0)+1.6xx10^(-19)xx2` . . . .(ii) `(hxx3xx10^(8))/(0.4xx10^(-6))=E_(0)+1.6xx10^(-19)xx1` . . . .(III) Substracting eq. (iii) from eq. (ii) we get `h[10^(15)-0.75xx10^(15)]=1.6xx10^(-19)` ltBrgt `hxx0.25xx10^(15)=1.6xx10^(-19)` `h=6.4xx10^(-34)`Js