What is the longest wavelength of light that can cause photoelectron emission from a metal that has a work function of 2.20 eV? (1 eV = 1.60 × 10^-19 J,c = 3.00 × 10⁸ m/s,h = 6.626 × 10^-34 J ∙ s) A)417 nm B)257 nm C)344 nm D)565 nm E)610 nm

Question

Quizplus · Accepted Answer

The wavelength can be found using the equation $ \lambda = \frac{hc}{E} $, where $ h $ is Planck's constant, $ c $ is the speed of light, and $ E $ is the energy in joules. First, convert the work function from eV to joules: $ 2.20 \, \text{eV} = 2.20 \times 1.60 \times 10^{-19} \, \text{J} $. Then, $ \lambda = \frac{6.626 \times 10^{-34} \times 3.00 \times 10^{8}}{2.20 \times 1.60 \times 10^{-19}} $, which calculates to approximately $ 5.65 \times 10^{-7} \, \text{m} $ or 565 nm.

What Is the Longest Wavelength of Light That Can Cause