RADIOACTIVITY
Definition:
This is the process by which an unstable nucleus disintegrates to form a more stable
nucleus with the release of energy
Background Radiation:
This is the radiation that is present in the environment all around us
Sources of background radiation
The sources of background radiation can be divided into natural sources and artificial
sources
1. Natural Sources of Background Radiation
- The air is radioactive because it contains Radon gas which is radioactive. Radon
seeps up to the surface from radioactive rocks underground. We are exposed to
radiation from this substance because we breathe in air all the time
- The ground contains radioactive substances and since we use materials from the
ground to build our houses, we get exposed to radiation from this source
- Foods and drinks are also slightly radioactive
- Radiation from space reaches us in the form of cosmic rays and this can be from
the sun or even from space. Most of these rays are stopped by the sun’s
, atmosphere. People flying aircrafts are at risk because they are high up in the sky
and so they are exposed to this radiation
2. Artificial sources of Background Radiation
- Medical sources e.g. X-ray machines and Gamma rays used to see inside the
body. Most of these radiations can cause cancer
- Nuclear power stations where uranium is used as fuel as well produce raditions
Detecting Radiations
Radiations can be detected using a Geiger-Muller tube
A Geiger-Muller tube is connected to a Geiger-Muller counter which records the
countrate
The countrate gives the rate at which radiation is detected
This is measured in counts per second or counts per minute
TERMS USED
1. Radioactive substance:
This is the substance that decays by emitting radiations from its atomic
nucleus
2. Radiation
This is the energy spreading out from a source carried by particles or waves
3. Countrate
Is the number of decaying radioactive atoms detected per second or per hour
or per minute
4. Radioactive decay:
This is the spontaneous disintegration of an unstable nucleus to form a more
stable nucleus with emission of radiations
Radioactive decay is a random process which means that it is impossible to
predict when the next decay will happen
NOTE:
Radioactive decay is not affected by external factors like Temperature
Question
Explain why some nuclei are unstable
Most elements have isotopes which are radioactive because their nuclei are
unstable. This is because the nucleus is too heavy while for some others, they
have too many neutrons
An unstable nucleus emits radiations in order to become more stable
Definition:
This is the process by which an unstable nucleus disintegrates to form a more stable
nucleus with the release of energy
Background Radiation:
This is the radiation that is present in the environment all around us
Sources of background radiation
The sources of background radiation can be divided into natural sources and artificial
sources
1. Natural Sources of Background Radiation
- The air is radioactive because it contains Radon gas which is radioactive. Radon
seeps up to the surface from radioactive rocks underground. We are exposed to
radiation from this substance because we breathe in air all the time
- The ground contains radioactive substances and since we use materials from the
ground to build our houses, we get exposed to radiation from this source
- Foods and drinks are also slightly radioactive
- Radiation from space reaches us in the form of cosmic rays and this can be from
the sun or even from space. Most of these rays are stopped by the sun’s
, atmosphere. People flying aircrafts are at risk because they are high up in the sky
and so they are exposed to this radiation
2. Artificial sources of Background Radiation
- Medical sources e.g. X-ray machines and Gamma rays used to see inside the
body. Most of these radiations can cause cancer
- Nuclear power stations where uranium is used as fuel as well produce raditions
Detecting Radiations
Radiations can be detected using a Geiger-Muller tube
A Geiger-Muller tube is connected to a Geiger-Muller counter which records the
countrate
The countrate gives the rate at which radiation is detected
This is measured in counts per second or counts per minute
TERMS USED
1. Radioactive substance:
This is the substance that decays by emitting radiations from its atomic
nucleus
2. Radiation
This is the energy spreading out from a source carried by particles or waves
3. Countrate
Is the number of decaying radioactive atoms detected per second or per hour
or per minute
4. Radioactive decay:
This is the spontaneous disintegration of an unstable nucleus to form a more
stable nucleus with emission of radiations
Radioactive decay is a random process which means that it is impossible to
predict when the next decay will happen
NOTE:
Radioactive decay is not affected by external factors like Temperature
Question
Explain why some nuclei are unstable
Most elements have isotopes which are radioactive because their nuclei are
unstable. This is because the nucleus is too heavy while for some others, they
have too many neutrons
An unstable nucleus emits radiations in order to become more stable
