Physics 2

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  • Created by: kelz0209
  • Created on: 18-04-14 13:52
How do smoke detectors work?
A weak alpha source is used to ionise the air between two electrodes so that a current can flow. If the alpha radiaton is absorbed by smoke, the current stops and the alarm sounds.
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Why is nuclear radiation dangerous?
Because it is ionising and can damage cells.
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Which type of radiation is most dangerous inside the body-alpha particles or beta particles?
Alpha particles.
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Describe two precautions that should be taken when handling radioactive sources in the lab.
Never look directly at the source/always handle the source with tongs/never allow the source to touch the skin/never have the source out of its lead-lined box for longer than necessary.
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Give one way in which people who work with radiation can be protected from it.
Wear lead aprons/work beind lead/concrete barriers.
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Which of the following is not a use of gamma radiation?
Smoke detetors.
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Nuclear radiation has many uses within medicine. Sugget two reasons why alpha sourcess aren't used as medical tracers.
Alpha radiation is stopped by the body's tissues and so wouldn't be detected externally. It is also strongly ionising which makes it dangerous inside the body.
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Suggest one reason why it is important that radioactive sources used in hospital sterilising machines have a long half-life.
So that the device lasts a long time and therefore doesn't need to be replaced as often.
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Explain why the dose of radiation given in radiotherapy is directed only at the tumour.
So that the dose to the rest of the body is minimised, to reduce damage to healthy cells.
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Nucleaar radiation can have harmful effects on the human body. Briefly explain how a low dose of nuclear radiation can cause cancer.
The radiation can collide with molecules in the body's cells, causing ionisation and damaging the cell. This can then result in mutant cells dividing uncontrollably, which is cancer.
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Describe what can happen to the body if it recieves a very high dose of nuclear radiation.
It can kill cell, which causes radiation sickness if a large part of the body is affected.
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A sample of a highly ionising raioactive gas has a half-life of two minutes. Describe what is meant by 'half life.'
The average time taken for half of the unstable nuclei in a sample to decay/ the time taken for the count rate or activity to half.
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The sample contains a number of unstable atoms. Calculate the fraction of these atoms that will be present after four minutes.
25%
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A worker holds a sample of the gas in a container using tongs. Suggest two other ways she could protect herself against exposure to radiation from the gas.
Keep exposure time short/ don't allow skin contact with sample/ hold container at arms length/ wear protective lead clothing/ put it in a lead container.
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Other cards in this set

Card 2

Front

Why is nuclear radiation dangerous?

Back

Because it is ionising and can damage cells.

Card 3

Front

Which type of radiation is most dangerous inside the body-alpha particles or beta particles?

Back

Preview of the front of card 3

Card 4

Front

Describe two precautions that should be taken when handling radioactive sources in the lab.

Back

Preview of the front of card 4

Card 5

Front

Give one way in which people who work with radiation can be protected from it.

Back

Preview of the front of card 5
View more cards

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