4d- Irridation, contamination, background radiation

Question 1

What does it mean if a substance is irridated?

Answer 1

It has been exposed to a radioactive source

Question 2

What does it mean if a substance is contaminated (referring to radiation)?

Answer 2

When unwanted radioactive atoms are onto/in a substance causing the substance to be contaminated.

Question 3

What radiation is most damaging from outside the body?

Answer 3

• Beta and gamma radiation → they are able to penetrate the skin

Question 4

What radiation is the most damaging if it’s inside the body?

Answer 4

• alpha radiation → localised irridation, beta and gamma are less dangerous when inside the body as they would mostly pass through it

Question 5

What is radiation dose?

Answer 5

Radiation dose is a measure of the risk of harm to your body due to exposure to radiation.

Question 6

What is radiation dose measured in?

Answer 6

sieverts (Sv)

Question 7

What is background radiation?

Answer 7

Low-level radiation that is present at all times

Question 8

What are sources of background radiation?

Answer 8

• naturally occuring unstable isotopes (literally in everything)
• from space (cosmic rays but thankfully the earth’s atmosphere absorbs alot of these from the sun)
• man-made sources → nuclear weapons or nuclear disasters

Question 9

What effect does radiation have on living cells?

Answer 9

Lower doses → Ionisation of molecules within the cells can result in a cell mutating and then dividing uncontrollably, resulting in a tumour.

Higher doses → Ionisation damages the cells so much that they die.

Question 10

What are the medical uses of radiation and how do they work?

Answer 10

Medical tracers

• Radioactive isotope is either ingested or injected into patient
• The progress of the substance can then be tracked through the body using an external detector
• Helps doctors see that a patient’s organs are properly functioning

Radiotherapy

• Treatment of cancer that uses ionising radiation to kill cancer cells
• Can damage other tissues in the process

Question 11

What is nuclear fission?

Answer 11

A type of nuclear reaction that releases energy through splitting apart larger more unstable atoms.

Question 12

What is the usual process for nuclear fission?

Answer 12

1. The unstable nucleus has to absorb a neutron before it can split
2. From this it forms two lighter elements around the same size that have kinetic energy in their store
3. Two or three neutrons are also released when the nucleus splits
4. Excess energy is carried away by gamma rays
5. The gamma rays and the kinetic stores of the left over neutrons can be used to heat water which can in turn use heat to turn generators

Question 13

What is nuclear fusion?

Answer 13

When two nuclei collide at speed to form a larger, heavier nucleus and in the process- producing energy.