P6 - Radioactivity

Question 1

Mass of an electron

Answer 1

0.0005

Question 2

Overall all charge of a nucleus is

Answer 2

Positive

Question 3

What are alpha particles

Answer 3

-> the nucleus of a helium atom

Question 4

What are beta particles

Answer 4

-> fast moving electrons

Question 5

What are gamma waves

Answer 5

A type of Em wave

Question 6

What is a neutron

Answer 6

A particle found in the nucleus

Question 7

Chemical symbol of alpha particles

Answer 7

⁴₂He

Question 8

Chemical symbol of beta particle

Answer 8

0
ß
-1

Question 9

Gamma wave chemical symbol

Answer 9

0
Y
0

Question 10

What is different about gamma wave compared to alpha and beta particles

Answer 10

Has no mass nor charge

This is because it is an Em wave

Question 11

Chemical symbol on neutron

Answer 11

1
n
0

Question 12

Why do particles decay

Answer 12

Because they have an unstable nucleus

The neutrons are not stable

Question 13

What does a neutron from when it is unstable

Answer 13

Forms a proton and a beta particle

Question 14

How do you record radiation

Answer 14

Use a Geiger-Müller counter

Question 15

How does a Geiger-Müller counter work

Answer 15

The clicks heard are small currents produced when the radiation ionises the gas inside the tube

Question 16

Order of penetration in alpha, beta and gamma

Answer 16

Least penetrating - alpha particles

Medium - beta particles

Most penetrating - gamma waves

Question 17

Order of ionisation alpha, beta and gamma

Answer 17

Least ionising - gamma

Medium - beta

Most ionising - alpha particles

Question 18

How can you stop alpha particles

Answer 18

Using a few sheets of paper

Question 19

How can you stop beta particles

Answer 19

Using a few mm of aluminium

Question 20

How do you stop gamma radiation

Answer 20

Buy using lead or a few m of concrete

However some still passes through

Question 21

Why is an alpha particle the most ionising

Answer 21

-> to ionise an atom, energy has to be transferred to it
-> alpha particles are able transfer more energy as they travel through the atom
-> which is also why they have a shorter range as the energy is used to ionise the atom

Question 23

What is radioactive activity

Answer 23

The radiation emitted from a radioactive substance every second

Question 24

What is activity measured jn

Answer 24

Becquerels

Question 25

What is half life

Answer 25

Time taken for activity to half AND time taken for unstable nuclei to decay

Question 26

What is contamination

Answer 26

-> occurs when radiation is taken INSIDE the body -> internal contamination CANNOT be removed

Question 27

What is irradiation

Answer 27

-> occurs when radioactive material is OUTSIDE the body -> radiation can travel into the body

Question 29

What are medical tracers

Answer 29

-> Radioactive isotope that is inhaled, swallowed or injected

Question 30

How does medical tracers work

Answer 30

The radioactive isotope is flame into the body The different organs absorb different amounts of the radiation The gamma camera is used to detect the radiation to show problems

Question 31

What is a gamma knife

Answer 31

Can be used to treat cancer Movable source of gamma radiation that moves around the body

Question 32

How does a gamma knife work

Answer 32

It’s a movable source of gamma radiation High dose is given to the tumour Low doses given to healthy cells, because it is moving

Question 33

Main sauces of background radiation

Answer 33

-> food and drink -> radon gas (rocks) -> ground and buildings -> cosmic rays -> artificial sources -> medical uses

Question 34

Give two reasons why there are a wide range of results around the count rate in an experiment measuring radioactivity

Answer 34

- radioactive decay is random - background radiation may influence results

Question 35

Why is it better to use a longer time interval when measuring count rate

Answer 35

-> less variation in count rate -> can give average count rate

Question 36

Why is an element with a low half dangerous

Answer 36

Means it decays faster, and also has a higher activity