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Radioactive Decay

Chapter summary, hard words and model exam answers for ICSE Class 10 Hindi.

Free online summary and notes (ICSE Class 10 Hindi). Read it here, no PDF download needed.

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Physics · CBSE 10 · ICSE 10 · GCSE (AQA, Edexcel, OCR)

Summary

Decay is spontaneous and random. Nothing triggers it, and temperature or pressure cannot change it.

Alpha is heavy and slow, beta is a light fast electron, gamma is a wave. All come from the nucleus.

Alpha is stopped by paper but rips apart many atoms. Gamma passes through lead but ionises little.

Ionising radiation can cause cancer. Protect with shielding, distance and short exposure time.

Hard words & meanings

radioactive decayspontaneous emission of particles or energy from an unstable nucleus
alpha particletwo protons and two neutrons, the same as a helium-4 nucleus
beta particlea fast electron made when a neutron becomes a proton
gamma rayhigh-energy electromagnetic radiation with no mass or charge
ionisationknocking electrons off atoms to form charged ions
penetrating powerhow far radiation travels through matter before being stopped
mass numbertotal number of protons and neutrons in a nucleus
atomic numberthe number of protons, which fixes the element
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