In the Geiger–Marsden alpha-particle scattering experiment, which graph best shows the number N(θ) of scattered alpha particles against scattering angle θ, on a logarithmic N scale? Image (four graph choices)
Options

Question

In the Geiger–Marsden alpha-particle scattering experiment, which graph best shows the number N(θ) of scattered alpha particles against scattering angle θ, on a logarithmic N scale? Image (four graph choices)

Options

G1 Physics · Accepted Answer

Step 1: Rutherford's scattering formula is dσ/dΩ ∝ 1/sin⁴(θ/2). Step 2: For fixed incident beam and detector acceptance, scattered-particle count is proportional to the differential cross-section. Step 3: At small scattering angles, sin(θ/2) is small; therefore N(θ) is very large. Step 4: As θ increases, sin(θ/2) increases and N(θ) decreases rapidly. Step 5: The graph showing a steep fall at small θ and a low tail at large θ matches this dependence. Final answer: Graph 3 (Option C).