Physics A-Level
Annihilation
What Annihilation means in Physics A-Level, as defined for AQA, OCR.
Definitions of Annihilation
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Reference: OCR
The process in which a positron and an electron convert the total rest mass into two gamma photons of equal energy, each about 511 keV, emitted in almost opposite directions.
When a particle meets its antiparticle they can convert their combined rest energy into photons, often two gamma-ray photons.
Topics that use Annihilation
- Particles, antiparticles and photons (AQA A-Level)
- Diagnostic methods in medicine (OCR A-Level)
Related terms
- Annihilation energy calculations
- Antiparticle
- Charge and quantum number symmetry
- Clinical diagnosis from count maps
- Coincidence detection
- Collimator
- Computer
- Conservation laws in particle interactions
Using Annihilation in the exam
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