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

Question

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 rounds to 2.5 eV.

The Threshold Wavelength for Photoelectric Emission of a Particular Substance