Uses Of Radioisotopes And Treatment

Question 1

Where does some unnatural radiation occur

Answer 1

Waste products, man made sources from industry and hospitals

Question 2

Radioisotopes uses

Answer 2

Tracers in industry/hospitals to find what is happening inside objects without breaking them up

To track dispersal of waste
Find leakages and blockages in underground pipes
Find routes of underground pipes

Question 3

How are gamma rays used to determine leaks and blockages in pipes

Answer 3

Radioactive material that emits gamma rays is put in pipes.
Gamma can penetrate through to surface and is tracked by detector above ground.
If leak: radioactive material will escape and be detected
If blockage: material won’t flow so stops being detected

Question 4

What radioactive substance is found in the bodies of animals and plants and used to date dead materials

Answer 4

Carbon-14

Question 5

How does Carbon-14 dating work

Answer 5

Radioactive Carbon-14 in atmosphere is unchanged for 1,000s of years.
When an object dies it no longer exchanges gases with the air.
As carbon-14 decreases, radioactivity decreases so ratio can be calculated against living matter to find age

Question 6

How are rocks dated

Answer 6

Naturally occurring radioactive uranium and lead is looked at

The ratio of uranium to lead determines age.

Question 7

How are alpha particles used in smoke alarms

Answer 7

Smoke alarms contain americum-241 which emits alpha particles causing air particles to ionise
Ions formed are attracted to oppositely charged electrodes in alarm resulting in a current (alarm works normally)
When smoke enters between the two electrodes, alpha particles are absorbed by smoke particles so cannot ionise the air
This causes a smaller current than normal, alarm sounds

Question 8

How can a material be made radioactive

Answer 8

By putting it into a nuclear reactor and allowing it to absorb extra neutrons

This makes the nucleus unstable so emits radiation

Question 9

How are x rays and gamma rays similar

Answer 9

Both electromagnetic waves

Question 10

How do x rays work

Answer 10

X rays and some nuclear radiation pass through soft tissue but less easily through bone

High speed electrons are fired at metal targets

Question 11

What is easier to control, gamma rays or x rays

Answer 11

X rays

Question 12

What precautions must a radiographer take

Answer 12

Stands behind lead screen to prevent accumulation of radiation

Question 13

How are gamma rays used in medicine

Answer 13

They damage cells so are used to treat cancer
Used as a tracer (beta and gamma rays pass through skin) to help diagnose problems such as blood clots
Sterilise medical equiptment, kills germs and bacteria

Question 14

How are gamma rays given out

Answer 14

Gamma rays are frequently given out after alpha or beta decay

The nucleus sometimes contains extra energy (after emitting alpha or beta particles) which is emitted as gamma radiation
This is high frequency electromagnetic radiation

Question 15

Why is it important tracers have a suitable half life

Answer 15

If radioactive tracers remain in the body too long, the patient could irradiate others

So patient is not radioactive for long

Question 16

How are gamma rays used to treat cancer

Answer 16

A wide beam of gamma rays focuses and rotates on tumour
Gamma radiation destroys cancer cells without surgery

There is minimised damage to rest of body but the treatment may destroy healthy cells, causing sickness

Question 17

What are tracers in the body

What must they emit

Answer 17

Small amount of radioactive material swallowed or injected
It must emit beta or gamma radiation to pass out of body for detection
Spreads through body, progress followed using radiation detecter outside body

Question 18

Where is most natural background radiation released from

Answer 18

Radioactive substances in soil and rocks (depending on rocks in the area)

Cosmic rays can also contribute

Question 19

Do gamma rays have any effect on structure of nucleus

Answer 19

Unlike alpha/beta decay, gamma has no effect on structure of nucleus