Rutherford’s gold foil (α-scattering) experimentरदरफोर्ड का स्वर्ण पर्णिका (α-प्रकीर्णन) प्रयोग

NCERT Fig 8.4 · interactive diagram

Parts and their functions

• Source of α-particles (α-कणों का स्रोत) — A radioactive element in a lead box gives a narrow beam of α-particles (positively charged; helium nuclei: 2 protons + 2 neutrons).
• Narrow beam of α-particles (α-कणों की पतली किरण) — Fast, heavy, positively charged particles aimed at the foil (Geiger and Marsden, 1911, under Rutherford).
• Extremely thin gold foil (अत्यंत पतली स्वर्ण पर्णिका) — Gold can be beaten into a sheet only a few hundred atoms thick.
• Fluorescent screen (प्रतिदीप्त पर्दा) — Glows where an α-particle hits it, so the scattering angles can be counted.
• Most passed straight through (अधिकांश सीधे निकल गए) — → Most of the atom is empty space.
• Some deflected by small angles (कुछ छोटे कोण से मुड़े) — They passed near the positive centre and were pushed aside a little.
• A few deflected by large angles (कुछ बड़े कोण से मुड़े) — → Positive charge is concentrated in a tiny region (nucleus).
• Very few bounced back (बहुत कम वापस लौटे) — Only a dense, heavy, positive nucleus can turn back a fast α-particle. This rules out Thomson’s spread-out model.

Original diagram drawn by Simple Learning Hub, based on NCERT Fig 8.4. Report a mistake