The work function of a particular metal is $4.20 \times 10 ^{- 19} \mathrm {~J}$ What is the photoelectric cutoff (threshold)wavelength for this metal? (c = 3.00 × 10⁸ m/s,h = 6.626 × 10^-34 J ∙ s) A)473 nm B)308 nm C)393 nm D)554 nm

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Explanation:The photoelectric cutoff wavelength is given by:$$\lambda = \frac{hc}{\phi}$$where:* h is Planck's constant (6.626 × 10^-34 J ∙ s)* c is the speed of light (3.00 × 10^8 m/s)* ϕ is the work function (4.20 × 10^-19 J)Plugging in the values, we get:$$\lambda = \frac{(6.626 	imes 10^{-34} \mathrm{~J \cdot s})(3.00 	imes 10^8 \mathrm{~m/s})}{4.20 	imes 10^{-19} \mathrm{~J}} = 4.73 	imes 10^{-7} \mathrm{~m} = 473 \mathrm{~nm}$$Therefore, the photoelectric cutoff wavelength for this metal is 473 nm.

The Work Function of a Particular Metal Is 4.20×10−19 J4.20 \times 10 ^{- 19} \mathrm {~J}4.20×10−19 J

The Work Function of a Particular Metal Is $4.20 \times 10 ^{- 19} \mathrm {~J}$