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The photoelectric threshold wavelength f...

The photoelectric threshold wavelength for Potassium having work function of 2eV is..........
(Take `h= 6.6 xx 10^(-34) J s. 1 eV = 1.6 xx 10^(-19) J , C = 3 xx 10^8 Ms^(-1)`)

A

1240 nm

B

310.7 nm

C

1860 nm

D

618.7 nm

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