small physics test Flashcards
types of energy transfers (4)
heating by radiation
mechanical/work
electrical/work
kinetic (particles)
alpha radiation + ionising properties + penetrating powers + distance + charge
- (alpha particles)2 protons and 2 neutrons
- strongly ionising
- stopped by paper
- a few centimetres
- positive (attracted to negative) (2+)
beta radiation (process) + ionising properties + penetrating powers + distance + charge
- high energy electrons form when a neutron splits into a proton and an electron
- moderately ionising
- stopped by aluminium
- tens of centimetres
- negative (attracted to positive) (-1)
gamma radiation + ionising properties + penetrating powers + distance + charge
- electromagnetic wave
- not very ionising
- stopped by concrete and lead
- very large distances
- neutral (0)
what happens to radiation after it travels for very large distances? (2)
- radiation becomes less intense as it travel further away from the radioactive material
- because the particles or rays become more spread out.
what is half life
how long it takes for half the nuclei of a piece of radioactive material to decay.
what happens to unstable nuclei
radioactive decay. they breakdown and change into a completely different type of atom.
what is an isotope
an atom with the same number of protons to an element but a different number of neutrons
ways of detecting radiation
and how?
- photographic film (gets darker when it absorbs radiation)
- Geiger-Muller tube (Each time it absorbs radiation, it transmits an electrical pulse to a counting machine.)
natural sources of background radiation (3)
cosmic rays - radiation that reaches the Earth from space
rocks and soil - some rocks are radioactive and give off radioactive radon gas
living things - plants absorb radioactive materials from the soil and these pass up the food chain
artificial sources of background radiation
- x rays
- nuclear weapons
- nuclear power
alpha symbol is a nuclear equation
4
α
2
beta symbol in a nuclear equation
0
β-
-1
neutron symbol is a nuclear equation
1
n
0
gamma symbol in nuclear equation
γ
what is irradiation?
Exposing objects to beams of radiation
what is contamination?
radioactive material is introduced into (or onto) an object.
what are the two types of radiation?
electromagnet and nuclear
where does nuclear radiation come from?
atomic nucleus from unstable isotopes
why is nuclear radiation released?
gives atoms greater stability
name a source of radiation
radon
define unstable nuclei
some nuclei are unstable, to become stable they fall apart; the particles and energy that are lost are called radiation
why is radiation dangerous?
radiation is ionising, it can damage DNA, causing cell mutations and therefore cancer
define ‘ionising’
electrons leaving atoms
