Radioactivity Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

How does ionising radiation work?

A

ionise atoms by removing electrons

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

What is an alpha particle?

A

a helium nucleus

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

What is the charge of an alpha particle?

A

+2e

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

What is the range of alpha in air?

A

1-2cm

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

What can alpha be stopped by?

A

sheet of paper

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

What is beta minus?

A

an electron

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

What is the charge of beta minus?

A

-e

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

What is the range of beta minus in air?

A

1-2m

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

What can beta minus be stopped by?

A

1-3mm of aluminium

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

What is beta plus?

A

a positron

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

What is the charge of beta plus?

A

+e

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

How far can beta plus travel in air?

A

not very as positrons get annihilated by electrons

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

What is gamma radiation?

A

EM wave

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

What is the range of gamma in air?

A

kilometers

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

What can gamma photons be stopped by?

A

few cm of lead

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

Which form of radiation is the most ionising?

A

alpha

17
Q

Which type of radiation is the least ionising?

A

gamma

18
Q

How does an unstable nucleus with more than 82 protons decay?

A

alpha- emitting a helium nucleus

19
Q

What is emitted in beta minus decay?

A

an electron

20
Q

What is emitted in beta plus decay?

A

a positron

21
Q

What is emitted in gamma decay?

A

surplus energy- gamma photon

22
Q

Define radioactivity:

A

random decay of an unstable nuclei

23
Q

Define half life:

A

time taken for half the number of active nuclei in a sample to decay

24
Q

Define activity:

A

rate of nuclei decay

25
Q

What is decay constant?

A

probability of decay of an individual nucleus per unit time

26
Q

What is ‘N’ representative of in the nuclear decay equation?

A

number of undecayed nuclei left in the source at time t

27
Q

What is the relationship between decay constant and half life?

A

inversely proportional

28
Q

What is carbon dating used for?

A

determining the age of organic materials

29
Q

Which isotopes have a constant ratio?

A

carbon 12 and carbon 14

30
Q

What happens to a living thing once it dies?

A

stops taking in carbon so the carbon 14 nuclei within the dead material decreases exponentially with time

31
Q

How can the age of a dead material be determined?

A

by comparing the carbon 12 to carbon 14 ratio of the dead thing with the same type of living thing

32
Q

Why can the C12 to C14 ratio not be assumed to remain constant?

A

it is affected by natural events such as volcanic eruptions as well as increased emissions from cars and burning fossil fuels

33
Q

Why is there large uncertainty when aging a relic? eg rocks

A

the value of the ratio in the past is not known