Term
| What are the three fundamental forces? |
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Definition
- Gravitational force
- Electromagnetic force
- Strong force
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Term
| What are the properties of the gravitational force? |
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Definition
Acts between all masses Always a force of attraction Is 1036 times weaker than electromagnetic force Acts at any distance but proportional to 1/[distance]2 Isn't important for subatomic particles
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Term
| What are the properties of the electromagnetic force? |
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Definition
Acts between charged bodies Can attract or repel Acts at any distance but is proportional to 1/[distance]2 Attractions and repulsions normally cancel for bodies bigger than molecules E.g holds electrons to nuclei in atoms, holds atoms together in compounds
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Term
| What are the properties of the strong force? |
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Definition
Acts between nucleons Is normally a force of attraction but becomes repulsive when nucleons are very close Is around 100 times stronger than the electromagnetic force Only acts over distances less then 10-14 m E.g holds nucleons together in nuclei
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Term
| What are the similarities and differences between particles and antiparticles? |
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Definition
Similarities: same particle with the same mass Differences: Opposite electrical charge |
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Term
| What is the difference between hadrons and leptons and give examples of both |
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Definition
Hadrons feel the strong force whereas leptons do not Hadron = proton, neutron Lepton = electron, muon |
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Term
| What can be said about the stability of hadrons (thinking about protons and neutrons)? |
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Definition
Most hadrons are very unstable and quickly decay into other particles Neutrons inside a stable nucleus are themselves stable, but free neutrons are unstable and have a half-life of about 15 minutes- decaying into a proton and an electron Protons are the most stable hadrons
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Term
| What happens when a particle and antiparticle meet? |
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Definition
| They annihilate each other and produce quanta (packets) of energy as gamma radiation (high-energy photons) |
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