Unit 2 - Nuclear Decay/Radiation Flashcards

1
Q

What is a beta particle?

A

An electron (released from the centre of an atom)

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2
Q

What is an alpha particle made of?

A

2 protons and 2 neutrons.

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3
Q

How far can an alpha particle travel?

A

Just a few cm in air and is stopped by paper.

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4
Q

Name the most ionising type of nuclear radiation.

A

Alpha - safe outside the body as it can’t get through skin, but very dangerous inside the body as it is so ionising.

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5
Q

Why is a radioactive sample with a short half life used in the body as a medical tracer?

A

It doesn’t last long in the body or There’s less of a risk of ionisation of cells as radioactivity levels decrease quickly.

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6
Q

What affects the half life of a radioactive sample?

A

Nothing, decay is a random process that can not be changed.

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7
Q

Define half life.

A

The time taken for the original count rate/number of radioactive atoms of a radioactive sample to decrease by half.

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8
Q

If a sample of radioactive atoms have a half life of 2 days how long would it take for the count rate to go from 2000 counts per second to 125 counts per second?

A

2000 - 1000 - 500 - 250 - 125 = 4 half lives = 8 days overall.

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9
Q

Why is a source of gamma radiation used as a medical tracer?

A

Gamma penetrates the skin and tissue so can be detected outside the body. It is also the least ionising.

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10
Q

Give a profession which would experience a higher level of background radiation than an average person.

A

Pilot (more cosmic rays)Frequent flyer/air hostess/Stewart (ditto)Worker in a nuclear power station

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11
Q

Give a natural source of background radiation.

A

Radon gasCosmic raysFood and drinkBuildingsRocks

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12
Q

Give an artificial source of background radiation.

A

Nuclear weapons testingNuclear power station leakMedical x rays, gamma rays produced in radiotherapy.

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13
Q

Which of these questions can not be answered by science?Where does background radiation come from?What is meant by the half life of a radioactive source?Should radioactive waste be dumped into the ocean?

A

Should radioactive waste be dumped into the ocean?This is a question in which the answer is opinion based. Experiments can not be done to answer this question.Watch out for ‘should’ questions! They want your opinion.

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14
Q

Which type of nuclear radiation is the least ionising?

A

Gamma. All nuclear radiation ionise cells but gamma is the most weakly ionising.

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