If the threshold wavelength for a certain metal is 2000

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If the threshold wavelength for a certain metal is 2000 Å, then the work-function of the metal is

1. 6.2 J
2. 6.2 eV
3. 6.2 MeV
4. 6.2 keV

Correct Option: B

Threshold wavelength (λ) = 2000 Å = 2000 × 10^–10 m. Work function

(W) =	hc	=	(6.6 × 10³⁴) × (3 × 10⁸)
	λ		2000 × 10^-10

= 9.9× 10^-19 J

=	9.9 × 10^-19	= 6.2 eV
	1.6 × 10^-19