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Physics AQA GCSE > Atoms and Radiation > Flashcards

Atoms and Radiation Flashcards

1
Q

What are the components of a Alpha particle?

A

2 protons
2 neutrons

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1
Q

Define radioactive decay

A

when an unstable nucleus become stable overtime by emitting ionsing radiation

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2
Q

Explain how a cloud chamber allows us to detect radiation?

A

A container full of air containing ionised air particles. Ionising radiation enters leaving a trail of ionised air molecules. The alcohol vapour condenses on the ionised air molecules showing the trail of radiation.

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3
Q

Why is gamma radiation used to sterilise medical equipment?

A

Sterilisation kills viruses and bacteria

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4
Q

How is beta particles used to make sure the right thickness of paper is being produced?

A

beta particles are fired through paper and if the thickness of the paper changes, fewer or greater beta particles will reach the detector and production can be stopped.

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5
Q

Explain how a Geiger Counter is used to detect radiation:

A

Ionising radiation enters a container full of low-pressure gas, the gas ionises the atoms, knocking off electrons out off the atom. The gas will now be able to conduct electricity and complete a circuit. Current flows between the electrodes and current produces a clicking noise. The count rate is the number of decays recorded per second.

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6
Q

How can a photographic film detect radiation?

A

A bright spot appears on the film whenever ionising radiation hits the film.

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7
Q

What are beta particles made up of?

A

high- speed electrons

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8
Q

How does a Beta particle form?

A

when a neutron changes into a proton

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9
Q

What is an isotope?

A

a variation of an element that consists the same number of protons but a different number of electrons

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10
Q

Explain how Gamma radiation is used to examine organs in the body?

A

A gamma-emitting isotope is placed into a person’s body, we than can trace the radiation’s movement in the body. Gamma is the most penetrating type of radiation so can leave the body without causing much damage. Gamma has a short half-life so the radiation can vanish quickly.

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11
Q

How is Alpha radiation used in smoke detectors?

A

Radioactive material fires alpha particles at the smoke detector. Alpha ionises the air and allows the current to flow between the electrodes. If there is smoke between the radioactive material and the smoke detector, fewer alpha particles will reach the detector as alpha is weakly penetrating and the current sops leading to the smoke alarm going off.

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12
Q

Why is Radon dangerous?

A

radon emits alpha particles and if we breathe in radon, alpha radiation will reach our lung tissue which increases the risk of lung cancer.

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13
Q

Explain how rocks are a from of background radiation:

A

rock like granite contain uranium salts which decay overtime releasing other radioactive nuclei.

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14
Q

What is alpha radiation stopped by?

A

paper or skin

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15
Q

Why is alpha radiation weakly penetrating?

A

cannot pass though objects easily as it is strongly ionising (relatively large)

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16
Q

What is Beta radiation stopped by?

A

aluminium

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17
Q

What is Gamma radiation a form of?

A

a form of electromagnetic radiation

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18
Q

What is gamma stopped by?

A

lead or metres of concrete

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19
Q

How is count rate measured?

A

A Geiger Muller Tube

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20
Q

What is the activity measured in?

A

Bq

21
Q

What is a half-life?

A

the time taken for an unstable isotope to halve from its original value

22
Q

Where does nuclear fission take place?

A

in a nuclear reactor

23
Q

What happens if nuclear fission is not controlled?

A

the rate of nuclear fission becomes faster and faster, starts a chain reaction which produces more and more energy and may lead to an explosion

24
Q

Explain how nuclear fission takes place in a nuclear reactor:

A

a slow-moving neutron is absorbed by the unstable nucleus which makes it even more unstable causing it to split apart into two smaller nuclei which then releases two or three neutrons as well as energy in the form of gamma radiation which then repeat the process again with another nuclei.

25
Q

What is the difference between spontaneous fission and induced fission?

A

Spontaneous fission is unforced and happens by itself while induced fission is the absorbing of a neutron in order to make the nuclei even more unstable.

26
Q

Define irradiation:

A

an object that has been exposed to ionising radiation

27
Q

What is nuclear fusion?

A

two small nuclei fusing together to become one larger nucleus

28
Q

How a chain reaction in a nuclear reactor can be controlled?

A

control rods can be lowered into the reactor to absorb neutrons to slow down the reaction

29
Q

What is the energy in nuclear reactors used for?

A

heats up water which turn into steam to drive turbines that are connected to an electricity generator

30
Q

List the advantages of nuclear energy:

A

uranium and plutonium fuel is cheap and produces larges amounts of energy, does not produce greenhouse gases.

31
Q

List the disadvantages of nuclear energy:

A

nuclear power plants are very expensive to build and nuclear waste is expensive to get rid of. There might be a risk of major disaster.

32
Q

Why is radiation harmful?

A

can damage the DNA in our cells

33
Q

How can you take precautions when working with radioactive isotopes?

A
  • wearing gloves
  • wearing a lead apron
  • lead walls/lead glass in extreme cases
34
Q

What was Thomson’s model of the atom?

A

The atoms was a ball of positive charge embedded with electrons.

35
Q

What was the alpha scattering experiment?

A

Alpha particles were fired at thin gold foil, most went straight through, some bounced back and some deflected.

36
Q

What were the results of the Alpha scattering experiment?

A

Most of the atom was empty space and the mass of the atom was concentrated at the centre which was positively charged.

37
Q

What is the nuclear model?

A

A positively charged nucleus surrounded by a cloud of negative electrons

38
Q

What did Niels Bohr propose?

A

electrons orbit the nucleus at fixed distances which are now known as electron shells.

39
Q

What did James Chadwick discover?

A

neutrons

40
Q

What is activity?

A

rate at which the source of unstable nuclei decays

41
Q

What is irradiation?

A

The process of exposing an object to nuclear radiation, does not become radioactive.

42
Q

How do we sterilise an object using irradiation?

A
  • placed in a lead shield to protect people
  • wrap object in plastic
43
Q

Why is peer review important?

A

allows researchers to share ideas and to test and evaluate each other’s wok

44
Q

Examples of man- made background radiation:

A
  • fallout from nuclear weapons
  • nuclear accidents
45
Q

How is nuclear radiation used in medicine?

A
  • radiotherapy
  • medical tracers
46
Q

What is radiotherapy used for?

A

cancer treatment to control or kill malignant cells

47
Q

How is gamma radiation used to explore internal organs?

A

we can place a gamma-emitting isotope into a person’s body and trace the radiation’s movement in the body. Gamma radiation is highly penetrating so can pass through easily and leave the body without causing much damage. Gamma has a short half-life so the radiation can vanish quickly

48
Q

What happens to neutron emitted during fission?

A

absorbed by more nuclei and trigger fission again

49
Q

Examples of natural background radiation:

A
  • rocks like granite
  • comic rays

Physics AQA GCSE (4 decks)

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