Radioactivity Flashcards Preview

Physics - AQA A Level > Radioactivity > Flashcards

Flashcards in Radioactivity Deck (22):
1

Geiger tube

Sealed tube with low pressure argon gas
When a particle of ionising radiation causing a voltage pulse

2

Inverse square Law

I = k/r²

3

Half life

Time taken for its mass to half

4

Activity of a radioactive isotope

A, is the number of nuclei that disintegrate per second
(Bq)
A = λN

5

Power of a radioactive source *

= AE
A activity
E energy per second

6

Number of radioactive particles remaining

N = N₀e^(-λt)

7

Decay constant, λ

Probability of an individual nucleus decaying each second

8

Relationship between half life and the decay constant

Half life = ln2 / λ

9

Carbon dating

Testing for carbon-14
Which is formed by cosmic rays and enters the plant cycle
5570 yrs half life

10

Argon dating

Argon-40 trapped in rocks was formed by K decay
1/9 chance of this decay (otw Ca)
1250 million yrs half life

11

Uses of radioactivity - tracers

Stable half-life to take measurements
Emit beta and gamma to detect outside of the system
Eg pipe leak or uptake of iodine by thyroid (8 days)

12

N-Z graph

Stable on the centre swoop

13

Metastable state

Long-lived excited state eg technetium, that can be separated from parent nuclei

14

Rutherford discovered the nucleus by...

Scattered alpha particles with gold foil, to see that some reflected

15

Rutherford discovered what about radiation?

It ionised air, making it conduct
3 types of radiation

16

Range of radiations

Alpha - few cm in air
Beta - m in air
Gamma - unlimited

17

Ionising effect of the radiations

Alpha - strong
Beta - weak
Gamma - very weak

18

Dangers of radiation

Destroys cell membranes
Damages by creating free-radicals. This disrupts cell division potentially causing cancer
Mutations that may be inherited

19

Safety measure when handling radiation

Film badge
Storage - sealed lead-lined containers
Robot/tongs handling
Limited use

20

Uses of radioactivity - engine wear

On a piston ring transferring to the oil. Made radioactive by bombarding with neutrons

21

Uses of radioactivity - thickness

β⁻ emitter and detector automatically instruct rollers on function to maintain thickness

22

Uses of radioactivity - power sources

On remote devices (satellites, weather sensors) thermocouple produces energy from heat