Discovery of the neutron (Chadwick, 1932)न्यूट्रॉन की खोज (चैडविक, 1932)Discovery of the neutron (Chadwick, 1932)

NCERT Section 13.2 · Class 12 Physics · Chapter 13 · interactive diagram

Parts and what they mean

• α source (α स्रोत) — Gives α-particles (helium nuclei, ⁴He: 2 protons + 2 neutrons).
• α-particles (α-कण) — Fast helium nuclei striking the beryllium.
• Beryllium target (बेरिलियम लक्ष्य) — Bombarded beryllium nuclei emit a highly penetrating neutral radiation.
• Neutral radiation = neutrons (उदासीन विकिरण = न्यूट्रॉन) — If it were photons, energy and momentum conservation needed far more energy than available. Chadwick showed it is a new neutral particle with mass ≈ proton mass.
• Target with light nuclei (हल्के नाभिकों वाला लक्ष्य) — The radiation knocked protons out of light nuclei such as helium, carbon and nitrogen.
• Knocked-out protons (बाहर निकले प्रोटॉन) — Their energies told Chadwick the mass of the neutral particle.
• Detector (संसूचक) — Counts the protons. Neutrons themselves leave no track because they have no charge.

Original diagram drawn by Simple Learning Hub, based on NCERT Section 13.2. Report a mistake