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

Question

Quizplus · Accepted Answer

The photoelectric cutoff wavelength is given by:$$\lambda = \frac{hc}{\phi}$$where:* h is Planck's constant* c is the speed of light* $\phi$ is the work functionPlugging in the given values, we get:$$\lambda = \frac{(6.626 	imes 10^{-34} \mathrm{~J \cdot s})(3.00 	imes 10^8 \mathrm{~m/s})}{4.20 	imes 10^{-19} \mathrm{~J}} = 473 \mathrm{~nm}$$Therefore, the correct answer is A.

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 $4.20 \times 10 ^ { - 19 } \mathrm {~J}$