Given :-
Energy required to remove an electron from Sodium = 2.3 eV
i.e. work function of Sodium = 2.3 eV

Energy of orange light photon of wavelength 6800 A⁰
= h (freq)
= h c / (lamda)
= [(6.6 x 10^-34 J.s) (3 x 10⁸ m / s)] / (6800 x 10^-10 m)
= 2.91 x 10^-19 J.
= [(2.91 x 10^-19) / (1.6 x 10^-19)] eV
= 1.82 eV

So, Sodium does not show a photoelectric effect for orange light having wavelength 6800 AU

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By :-   Dr. A. W. Pangantiwar