A hydrogen atom makes the transition n=3→1. The emitted photons fall on a material of work function 5.1 eV. Estimate the stopping potential in volts.
Physics · Photoelectric effect and dual nature of matter
JEE Mains Practice

Question

A hydrogen atom makes the transition n=3→1. The emitted photons fall on a material of work function 5.1 eV. Estimate the stopping potential in volts.

G1 Physics · Accepted Answer

Step 1: Photon energy is Eγ = hc/λ and Einstein's equation is Kₘₐₓ = Eγ−φ. Step 2: If a stopping potential is involved, Kₘₐₓ = eVₛ. Step 3: Using the two stated cases eliminates φ or gives it directly. Final: 7.