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Describe the nature of  alpha particles

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An alpha particle is basically the nucleus of a Helium atom, with a charge of 2+, consisting of 2 protons and 2 neutrons.

Compared to beta and gamma radiation, alpha is much heavier and slower 

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Describe the nature of Beta particles

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Describe the nature of Gamma radiation

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Gamma radiation is a high energy electromagnetic radiation. It travels at 3 x 10⁸ m.s^-1

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State what is ionisation and describe what effect it has on a neutral atom

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Ionisation is when an atom gains or loses an electron.

An electron is negative.

When a neutral atom gains an electron it becomes negative and when it loses an electron it becomes positive 

List alpha, beta, and gamma radiation in terms of their ionising effects.

Justify your answer.

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Alpha is most ionising, whilst gamma is least ionising.

Alpha particles have a charge of 2+ and are larger than beta and gamma particles, therefore it is most ionising.

Beta is very small, but has a charge of -1, therefore it is mildly ionising.

Gamma on the other hand has no charge and moves as fast as the speed of light, therefore it is the least ionising. 

List alpha, beta, and gamma radiation in terms of their penetration ability. 

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Gamma is most penetrating, whilst alpha is the least penetrating. 

• alpha is absorbed by a thin sheet of paper
• beta is absorbed by millimeters of aluminium
• gamma is absorbed by lead

Define  activity in terms of the number of nuclear disintegrations/decaying and time.

State what an activity of 180 Bq mean?

Activity is the number of nuclei decaying per second.

An activity of 180 Bq means there are 180 nuclei decaying per  second.

State the..... 

1. Average annual background radiation in UK: 
2.  Annual effective dose limit for member of the public: 
3. Annual effective dose limit for radiation worker: 

 Average annual background radiation in UK: 2·2 mSv.

 Annual effective dose limit for member of the public:       1 mSv.

 Annual effective dose limit for radiation worker: 20 mSv.

Define half-life

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The HALF LIFE of a radioactive source is the time it takes for the activity to decrease by half.

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Describe nuclear fission in terms of a chain reaction

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A large mass nucleus absorbs a neutron.

The large mass nucleus splits into 2 smaller mass nuclei.

Energy  and more neutrons are released.

The neutrons causes the process to repeat itself.

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Describe nuclear fusion

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Nuclear fusion occurs when 2 small mass nuclei combine to form a larger mass nucleus.

Energy is released.

Explain plasma containment during fusion reaction

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Large magnets prevents the very hot plasma from touching the walls of the doughnut shaped containment.

• If the very hot plasma touches the wall of the containment the plasma will be cooled and the fusion reaction may stop.
• The walls may be damaged as well.

Describe how electricity is generated from nuclear power.

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• The heat generated during the fission and fusion reactions heat the water.
• The water turns into steam.
• The steam turns the turbine, which turns coil in a magnetic field.
• This generates electricity. 

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Describe uses of nuclear radiation in traces

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Describe radiotherapy to treat cancer

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Convert the following to m:

1. 5 nm
2. 80 km
3. 40 mm
4. 700 μm
5. 60 Mm
6. 500 Gm

Convert the following to m:

1. 5 nm = 5 x10^-9 m
2. 80 km = 80 x 10³ m 
3. 40 mm = 40 x 10^-3m 
4. 700 μm = 700 x 10^-6 m
5. 6Mm = 6 x 10⁶m 
6. 5Gm = 5 x 10⁹m or 

Write the equations for absorbed dose, equivalent

dose, and equivalent dose rate.

Also include the units of each component.

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Describe a neutral atom

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A neutral atom has equal number of electrons and protons.

State the charges of the 3 types of nuclear radiation

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Remember: opposite charges attract

Positive alpha is attracted to the negative plate.

Negative electron is attracted to the positive plate.

Neutral gamma is not affected by the charged plates.

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A radioactive substance has an activity of 2 MBq.

Calculate the number of nuclei that will decay in 2 minutes.

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A tumour with a mass of 30g absorbs 0·9 J of energy during a course of treatment.

Calculate the absorbed dose.

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A sample of tissue receives an absorbed dose of 80 mGy from alpha radiation.

Calculate the equivalent dose.

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A sample of tissue is exposed to 15 µGy of alpha radiation and 20 µGy of gamma radiation. Find the total equivalent dose received by the tissue.

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For alpha

H=Dwr

H = 15 μGy x 20

    = 300 μSv

For gamma

H=Dwr

H = 20 μGy x 1

    = 20 μSv

Total equivalent dose = 300 μSv +20 μSv =320 μSv

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Describe how the apparatus could be used to obtain the experimental data required to produce this graph.

3 marks

• Measure the count in a set time interval (1)
• Repeat at (regular) intervals (1)
• Measure background (count) and subtract (1)

State a use of nuclear radiation.

•  treating cancer
• tracers
• sterilisation
• smoke detectors
• measuring thickness of paper