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AQA Physics GCSE > Uses and dangers of radiation > Flashcards

Uses and dangers of radiation Flashcards

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1
Q

what is irradiation

A

the process of exposing an object to a source of radiation

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2
Q

what is irradiation used in

A
  • to preserve fruit and destroy any bacteria on it
  • to sterilise surgical equipment
    both using gamma rays
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3
Q

how are gamma rays used to kill cancer cells

A

the beams are aimed at the tumour from many different directions to maximise the dose on the tumour but to minimise the dose in healthy soft tissue, enough to kill the tumour, but so that healthy tissue isnt damaged

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4
Q

what needs to be considered when using radioactive sources in medical applications

A

the nature of decay (whether its alpha beta or gamma)
- toxicity
- half life

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5
Q

advantages of irradiation

A
  • sterilisation can be done without high temperatures
  • it can be used to kill bacteria on things that would melt
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6
Q

disadvantages of irradiation

A
  • it may not kill all bacteria on an object
  • it can be very harmful, could expose people’s cells to damage and mutation
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7
Q

what is radioactive contamination

A

when unwanted radioactive isotopes end up on other materials

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8
Q

when is contamination used

A
  • used as tracers
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9
Q

why is medical contamination used

A
  • the isotopes used have very short half lives, meaning after a couple of days there will hardly be any radioactive material in the persons body
  • the isotopes are not poisonous
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10
Q

advantages of radioactive contamination

A
  • radioactive isotopes can be used as medical and industrial tracers
  • using isotopes with shorter half lives means exposure will be limited
  • imaging processes can replace some invasive surgical procedures
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11
Q

disadvantages of radioactive contamination

A
  • radioactive isotopes may not go where they are wanted
  • it can be difficult to ensure that the contamination is fully removed so small amounts of radioactive material may be left behind
  • exposure to radioactive materials may potentially damage healthy cells
  • hazardous as radioactive atoms emit ionising radiation
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12
Q

what is the difference between irradiation and contamination

A

irradiation
- is when the object is exposed to a radiation source outside the object
- doesnt cause the object to become radioactive
- can be blocked with shielding
- stops as soon as the source is removed

HOWEVER
contamination
- is when the radioactive source is on or in the object
- the object will stay radioactive as long as the source is on or in it
- once an object is contaminated, the radiation cannot be blocked
- can be very difficult to remove contamination

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13
Q

how can we mange the risks of radiation

A
  • wear protective clothing to prevent the body from becoming contaminated
  • avoid contact with bare skin, and dont taste the sources
  • wear face masks to avoid breathing in materials
  • limit exposure time, so less time is spent around radioactive material
  • handle radioactive with tongs
  • keep material shielded when not in use
  • wear gloves
  • wear lead aprons
  • use a radiation monitor
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14
Q

what is background radiation

A

low level nuclear radiation that is present in natural and man made sources

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15
Q

why is it better to have a sample with a longer half life than short

A
  • because when the radioactive sample halves, a radioactive particle is emitted, meaning that there is a higher chance of irradiation. If it halves more frequently, that increases the chance of exposure to radioactive material
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16
Q

what is nucleur fission

A

the splitting of a large nucleus into 2 smaller nuclei and kore nutrons

17
Q

what are the steps of nuclear fission

A
  1. the unranium nucleus absorbs a neutron and the nucleus splits into two daughter nuclei
  2. The nucleus also emits two or three more neutrons and gamma rays
    - energy is also released
  3. the neutrons can now be absorbed by more unstable nuclei
18
Q

what are chain reactions controlled in

A

a nuclear reactor

19
Q

what is nuclear fusion

A

the joining of two light nuclei to form a heavier nucleus, mass is converted into energy and released as radiation when this happens

20
Q

when sterilising an object with radiation, how do we stop bacteria from getting in

A

by placing a plastic wrapper around it

21
Q

how to sterilise an object with radiation

A
  • place it in a plastic wrapper
  • place the object near a radioactive isotope that emits gamma radiation
  • this must be inside a lead shield, to protect workers from radiation
  • withdrawing the lead shield allows gamma radiation to irradiate the object, and the gamma radiation kills any bacteria present
22
Q

why doesnt the object become radioactive when irradiated

A

because the object only comes in contact with the radiation, not the radioactive isotope itself

23
Q

effects of each type of radiation on the body

A

alpha : strongly ionising but easily stopped by dead cells on the skins surface. can be dangerous if inhaled or swallowed
beta : quite ionising, but can penetrate skin and damage cells
gamma : least ionising, can pass straight into the body and out

24
Q

why is peer review important

A

so that findings can be checked and to prevent false claims

25
Q

natural sources of radiation

A
  • rocks
  • cosmic rays - high energy particles which crash into the earths atmosphere
26
Q

man made sources of radiation

A
  • nuclear weapon testing
  • accidents at nuclear power station
27
Q

what can your exposure to radiation be affected by

A
  • your location
  • your occupation
28
Q

how is nuclear radiation used in medicine

A
  • exploring internal organs
  • controlling or destroying unwanted tissue
29
Q

how to check the function of a thyroid gland

A
  • patient drinks radioactive iodine
  • it emits gamma radiation which passes out of the body and can be detected
  • if the scan shows that the thyroid has absorbed to much or too little iodine then the doctors can use this to diagnose
30
Q

what are tracers used for

A
  • finding tumours
  • they emit gamma rays
31
Q

What are some issues with the radiation in medicine?

A
  • The tracer emit radiation that can pass out of the body and be detected, like beta or gamma
  • the tracer should not be strongly ionising to minimise damage to body tissue
  • The tracer must not decay into another radioactive isotope
  • It must have a short half life, so that it’s not present in the body for a long period
32
Q

What is radiotherapy?

A

Using ionising radiation to destroy certain cancers

33
Q

How does radiotherapy work?

A

The machine contains a source of gamma radiation.

Gamma rays pass into the body and destroy the tumour.

34
Q

problems with radiotherapy

A
  • healthy tissue may be damaged as the radiation passes through the body
35
Q

What are the benefits of using radiation inside the body?

A

The radiation is treated very precisely to the tumour, so there is less damage to healthy tissue

36
Q

what are explosions in a nuclear weapon caused by

A

uncontrolled fission chain reaction

37
Q

what is a controlled chain reaction used for

A

used in a nuclear reactor

AQA Physics GCSE (38 decks)

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