Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

IGCSE PHYSICS > Unit 4 - Radioactivity > Flashcards

Unit 4 - Radioactivity Flashcards

You may prefer our related Brainscape-certified flashcards:
Physics 101 flashcards AP® Physics flashcards
1
Q

What is the atomic number

A

The number of protons in the nucleus (bottom number on element card)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the mass number

A

Also know as the nucleon number, the mass number is the total of protons and neutrons in an atoms (top number on element card)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are alpha particles, beta particles, and gamma rays

A

They are ionising radiations emitted from unstable nuclei in a random process

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Properties of an alpha particle

A

Nature: a nucleus (2 protons, 2 neutrons)
Ionising: very strong
Penetrating: sheet of paper

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is an alpha particle made up of

A

2 protons, 2 neutrons

A helium nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Properties of a beta particle

A

Nature: 1 electron
Ionising: medium
Penetrating: aluminium sheet (few mm thick)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Properties of a gamma ray

A

Nature: electromagnetic wave
Ionising: weak
Penetrating: thick lead

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Effects of emitting an alpha particle

A

Mass number decreases by 4

Atomic number decreases by 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Effect of emitting a beta particle

A

Atomic number increases by 1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Effect of emitting a gamma ray

A

No change in mass or atomic number

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What device is used to detect radiation

A

A Geiger-Muller tube and counter

Photographic film can show its there but not measure it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is background radiation

A

This is radiation detected with no source present

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Causes of background radiation

A

Medical and industrial uses, rocks (radon gas), cosmic rays

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the units of radioactivity

A

Activity is measured in Becquerels

1Bq = 1 emission per second

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is meant by the term ‘half life’

A

The half life of a radioactive source is the time taken for the activity to half

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Uses of radioactivity in medicine

A
  • Radioactive tracers let doctors see the inside of our bodies. The organ absorbs the tracer so it can be seen through a machine
  • colbalt 60 emits very energetic gamma rays that kill bacteria (as well as cells) so it is used for sterilisation
17
Q

Uses for radioactivity in industry

A
  • tracers detect leaks in underground pipes (saving money + time)
  • used to measure the thickness of paper
18
Q

How does carbon dating work

A

Carbon-14 is a radioactive isotope found in the air and in all living organisms.
Once an organism dies, it stops taking in carbon-14. The carbon-14 it contained at the time of death decays over a long period of time, and the radioactivity of the material decreases.
The approximate time since the organism died can be measure by the amount of carbon-14 left in it and the half life of carbon-14

19
Q

Risks of ionising radiation

A

Can cause mutations to DNA that cause cancer

Can cause damage to cells and tissue

20
Q

How to reduce risk from radiation

A

Increase distance from source
Decrease exposure time
Use protective material

21
Q

Problems with storing radioactive waste

A

It stays active for thousands of years and needs to be stored safely
Could be used by terrorists

22
Q

Results of Geiger and Marsdens experiments with gold foil

A

It proved that an atom had a concentrated positive charge in there centre surrounded by lots of empty space.

23
Q

How can we use uranium to make energy

A

The nucleus of U-235 can be split by collision with a neutron (fission), this process releases lots of energy in the form of kinetic energy (heats the water, steam, turns the generator) and fission products

24
Q

How does carbon dating work

A

Carbon-14 is a radioactive isotope found in the air and in all living organisms.
Once an organism dies, it stops taking in carbon-14. The carbon-14 it contained at the time of death decays over a long period of time, and the radioactivity of the material decreases.
The approximate time since the organism died can be measure by the amount of carbon-14 left in it and the half life of carbon-14

25
Q

Risks of ionising radiation

A

Can cause mutations to DNA that cause cancer

Can cause damage to cells and tissue

26
Q

How to reduce risk from radiation

A

Increase distance from source
Decrease exposure time
Use protective material

27
Q

Problems with storing radioactive waste

A

It stays active for thousands of years and needs to be stored safely
Could be used by terrorists

28
Q

Results of Geiger and Marsdens experiments with gold foil

A

It proved that an atom had a concentrated positive charge in there centre surrounded by lots of empty space.

29
Q

How can we use uranium to make energy

A

The nucleus of U-235 can be split by collision with a neutron (fission), this process releases lots of energy in the form of kinetic energy (heats the water, steam, turns the generator) and fission products

30
Q

Fission of Uranium-235

A
  • neutrons are fired at U-235 (found in fuel rods)
  • U-235 absorbs these neutrons
  • 2 daughter nuclei are produced, as well as some very fast moving electrons
  • moderators slow down these electrons so that they can collide with more U-235
  • control rods absorb neutrons, they can be lowered into the reactor to slow down/stop the chain reaction
31
Q

Rutherfords nuclear model of the atom

A

Positive nucleus in the centre (protons and neutrons), surrounded by shells of electrons

IGCSE PHYSICS (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions