[9] Radioactivity Flashcards

1
Q

What is background activity?

A

Background activity is radiation that is always a constant. It is emitted from our surroundings, walls, rocks, people. It is naturally occurring.

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2
Q

Sources of Background Radiation

A
Cosmic
Terrestrial
Dietary
Medical
Consumer products
Radon
Other
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3
Q

How can the background count be measured?

A

Using a Geiger Muller Tube and Scalar counter

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4
Q

Describe the process of ionisation due to radioactive substances emitting ionising radiations (Alpha, Beta, Gamma)

A

During ionisation an electron or electrons are knocked off atoms or molecules so that they have become positively charged.

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5
Q

Order the three types of ionising radiation in terms of penetrating distance from smallest to largest.

A

Alpha
Beta
Gamma

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6
Q

Order the three types of ionising radiation in terms of ionising potential from highly ionising to weakly ionising.

A

Alpha
Beta
Gamma

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7
Q

Order the three types of ionising radiation in terms of relative atomic size from smallest to largest.

A

Gamma
Beta
Alpha

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8
Q

Uses of radioactivity in industry

A

Thickness gauge - If a radioisotope is placed on one side of a moving sheet of material and a GM tube on the other, the count-rate decreases if the thickness increases. This technique is used to control automatically the thickness of paper, plastic and metal sheets during manufacture.

  • Sterilisation of products
  • Electricity generation

Radioactive tracers - The progress of a small amount of a weak radioisotope injected into a system can be ‘traced’ by a GM tube or other detector. The method is used in industry to measure fluid flow in pipes

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9
Q

Uses of radioactivity in medicine

A

Radioactive tracers - The progress of a small amount of a weak radioisotope injected into a system can be ‘traced’ by a GM tube or other detector. The method is used in medicine to detect brain tumours.

Radiotherapy - Gamma rays from strong cobalt radioisotopes are replacing X-Rays in the treatment of cancer.

Sterilisation - Gamma rays are used to sterilise medical instruments by killing bacteria.

• Treatment of cancerous tumours

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10
Q

Uses of radioactivity in agriculture

A

Radioactive tracers - The progress of a small amount of a weak radioisotope injected into a system can be ‘traced’ by a GM tube or other detector. The method is used in agriculture to study the uptake of fertiliser by plants.

Sterilisation - Gamma rays are used to ‘irradiate’ some foods, again killing bacteria to preserve the food for longer.

  • Improve food crops
  • Control insect pests
  • Measure soil moisture content
  • Measure erosion rates
  • Salinity
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11
Q

During the fusion reaction some mass is converted to energy

A

E = MC^(Squared)

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