The threshold wavelength for photoelectric emission of a particular substance is 500 nm. What is the work function (in eV)? A) 4.2 B) 4.0 × 10−¹⁹ C) 4.0 × 10−¹⁰ D) 2.5 × 10−¹⁹ E) 2.5

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Quizplus · Accepted Answer

The work function (ϕ) is calculated using the formula ϕ = hc/λ, where h is Planck's constant (4.135667696 × 10^-15 eV·s), c is the speed of light (3 × 10^8 m/s), and λ is the threshold wavelength (500 nm = 500 × 10^-9 m). Substituting these values gives ϕ ≈ 2.48 eV, which is approximately 2.5 eV.

The Threshold Wavelength for Photoelectric Emission of a Particular Substance