Atomic Physics - Paper 1 Flashcards Preview

AQA Physics Paper 1 11-A > Atomic Physics - Paper 1 > Flashcards

Flashcards in Atomic Physics - Paper 1 Deck (62)
Loading flashcards...
31

Define irradiation

The process of exposing an object to radiation. the object does become radioactive. e.g. killing bacterial on fruit to increase its shelf life.

32

How should radioactive sources be used safely?

Use only for a short period of time.
Keep source at arms length
Point source away from yourself
Stored in a lead lined box with a radioactive symbol

33

What is background radiation?

Radiation that is around us all the time

34

State some sources of natural background radiation?

Rocks, cosmic rays, food

35

State some sources of man made background radiation

X-rays, nuclear bombs, nuclear power stations

36

What factors can affect the level of background radiation a person receives?

occupation e.g. radiotherapist, pilot
Location - Background radiation increase with altitude.

37

State the units of radiation dose

Sieverts (Sv)

38

What type of radiation and half life should be used with a medical tracer.

Gamma with a short half life - 6 hours

39

What type of radiation and half life should be used with a smoke detector.

Alpha with a long half life - 400 years

40

Describe nuclear fission

Splitting of a large unstable nucleus eg Uranium or plutonium

41

What is required to start fission

The unstable nucleus must absorb a neutron

42

What is released after fission

2/3 neutrons
Lots of energy

43

What is a chain reaction?

One neutron is absorbs by one Uranium nucleus. this undergoes fission and realises 2 or 3 neutrons. these neutrons can cause fission in 2 or 3 more uranium nucleus. the process can keep repeating.

44

Describe nuclear fusion

The joining of two light nuclei to form a heavier nucleus.

45

Where does fusion take place naturally?

In all stars

46

What is released by fusion

Energy

47

What is the majority of the mass of an atom?

The nucleus, as the mass of an electron is almost zero compared to the mass of protons and neutrons

48

What was Dalton's theory about the atom?

all matter is made of small invisible units called atoms

49

What was Thomson's theory about the atom?

He discovered the electron and therefore knew the atom was made up of charged particles. He introduced the Plum Pudding Model

50

What was Rutherford's theory about the atom?

following the alpha particle scattering experiment he update the plum pudding model to the Nuclear Model; that most of the mass of the atom was concentrated in the nucleus which carries a positive charge

51

What was Bohr's theory about the atom?

Bohr updated the Nuclear model to show that electrons orbit the nucleus in certain energy levels

52

What was Chadwick's theory about the atom?

discovered the neutron

53

Why did the discovery of electrons mean that Dalton's model of the atom needed to be updated?

That atoms were not the smallest thing anymore, as the electron was smaller than the atom

54

What are the different types of nuclear radiation?

Alpha
Beta
Gamma
Neutron

55

What happens to the mass and charge of the nucleus during alpha decay?

Mass (nucleon) number goes down by 4
Number of protons goes does by 2

56

What happens during beta decay?

A neutron decays into a proton creating the beta particle which is fired out of the nucleus

57

What happens to the mass and charge of the nucleus during beta decay?

Mass (nucleon) number stays the same
Number of protons goes up by 1

58

What happens to the mass and charge of the nucleus during gamma decay?

Mass (nucleon) number stays the same
Number of protons stays the same

59

What happens when radioactive radiation strikes an atom?

It can knock an electron off an atom - ionisation

60

What is the safest type of radiation to have inside the body?

Gamma as it's the least ionising and escapes easily