Nucleon number is the total number of protons and neutrons in a nucleus
Isotopes are atoms having the same proton number but different nucleon number
Radioisotope is an unstable isotope that will emit radioactive radiations
Alpha particle
- helium nucleus
- low penetrating power
- high ionising power
- can be stopped by a piece of paper
Beta particle
- electron
- moderate penetrating power and ionising power
- can be stopped by several mm of aluminium
Gamma ray
- electromagnetic wave
- high penetrating power
- low ionising power
- can be stopped by several cm of lead
Suitable detector - Geiger-Muller tube (G-M tube)
Half-life is the time taken for the activity of a radioactive sample to fall to half of its original value
Application of radioisotopes
- half life
--> human body - short - less dangerous to human body
--> factory - long - can be used for long time
- penetrating power
--> human body - low / medium
--> factory - medium / high
- ionising power
--> human body and factory - low
- state of material
--> solid - easy to handle
--> liquid - easy to dissolve
Nuclear fission is a process of splitting of a heavy nucleus into two or more lighter nuclei
When a high speed neutron hits to a uranium nucleus, lighter nuclei and a few neutrons are produced.
The neutrons produced will hit to some other uranium nuclei to produce more fissions and more neutrons.
A chain reaction occurs when the process is continuing and self-sustaining
The chain reaction process will stop when all the uranium nuclei had been split by the neutrons
