Q.12:- Electrons are emitted with zero velocity from a metal surface when it is exposed to radiation of wavelength 6800 Å. Calculate threshold frequency (νo) and work function (wo) of the metal.
c = νλ
∴ νo = c/λo = 3.0×108 ms-1/6800×10-10 m = 4.14×1014 s-1
Work function (wo) = hνo = 6.626×10-34 Js×4.14×1014 s-1 = 2.92×10-19 J