Types of Radiation - Atomic Structure Physics

Question 1

Isotope

Answer 1

Atoms with different number of neutrons

Question 2

Radioisotope

Answer 2

Isotope that emits radiation because the mass in the atom’s nucleas becomes too heavy. The attraction in the nucleas decreases and becomes unstable

Question 3

What is the approximate size of an atom?

Answer 3

1 X 10⁻¹⁰

Question 4

What is the size of a radius of a nucleas?

Answer 4

less than ¹⁄₁₀₀₀₀

Question 5

What did Ernest expect of the alpha particles when they went through the gold foil?

Answer 5

They would be deflected

Question 6

What is an alpha particles made from and how?

Answer 6

If the nucleus has too few neutrons, it will emit a ‘package’ of two protons and two neutrons called an alpha particle.
Helium ion, two neutrons, two protons and no electrons.

Question 7

What is the ionising power of an alpha particle?

Answer 7

Highly ionising due to its size - dangerous if ingested

Question 8

What is an alpha particle’s range in air?

Answer 8

Less than 5cm

Question 9

What is the penetrating power of an alpha particle?

Answer 9

Few mm of Skin/paper

Question 10

What is penetrating power?

Answer 10

How far into a material a radiation will be able to go

Question 11

What is the mass and atomic number of an alpha particle?

Answer 11

Mass number = 4
Atomic number = 2
(same as Helium)

Question 12

What does ionising mean?

Answer 12

The ability of a type of radiation to turn an atom into an ion

Question 13

What is a beta particle?

Answer 13

Fast-moving electron

Question 14

What forms a beta particle?

Answer 14

If the nucleus has too many neutrons, a neutron will turn into a proton and emit a fast-moving electron

Question 15

What is the ionising power of beta radiaition?

Answer 15

Moderately ionising

Question 16

What is a beta particle’s range in air?

Answer 16

1 metre in the air

Question 17

What is a beta particle’s penetrating power?

Answer 17

3mm aluminium foil

Question 18

What is gamma radiation?

Answer 18

Waves of electromagnetic radiaiotn

Question 19

What is gamma radiation?

Answer 19

Waves of electromagnetic radiaiotn

Question 20

When is gamma radiation emitted?

Answer 20

Emitted by an unstable nucleus of an atom during radioactive decay.

Question 21

How ionising is gamma radiation?

Answer 21

Weakly ionising

Question 22

How penetrating is gamma radiaiton?

Answer 22

Highly penetrating

Question 23

What stops gamma radiation?

Answer 23

Lead/ concrete

Question 24

What is the range of gamma radiation?

Answer 24

1km

Question 25

# Alpha and Beta radiation What are the characteristics of alpha and beta particles in terms of their deflection in an electric field?

Answer 25

* Alpha and beta particles are deflected in opposite directions in an electric field * beta particles are delfected more * alpha particles have a greater charge than beta but beta have much less mass * beta have a greater specific charge than alpha

Question 26

How do smoke alarms work?

Answer 26

1. Americium 241 is an isotope that releases alpha particles 2. The alpha particles ionise the air 3. This created a current between the 2 charged plates 4. The alarm won't sound 5. Smoke slows down the ions betweent the 2 charged plates 6. This decreases the current 7. The current detector detects a decrease and the alarm goes off

Question 27

How is activity measured?

Answer 27

geiger-muller tube

Question 28

what is the count-rate?

Answer 28

number of decays recorded each second by a detector

Question 29

count rate vs activity

Answer 29

count rate can include background radiation

Question 30

4 types of radiation

Answer 30

alpha, beta, gamma, neutron

Question 31

whats contamination

Answer 31

unwanted radioactive isotopes end up on other materials

Question 32

2 natural main sources of background radiation

Answer 32

* Radioactive rock - granite * cosmic rays from space - v high energy particles whichtravel through space and crash into earths atmos

Question 33

2 man made sources of back ground radiation

Answer 33

* fall out from nuclear weapons testing - released radioactive isotopes into environment * nuclear accidents

Question 34

what is radiation dose measured in? what is 1mSv = to

Answer 34

sieverts 1mSv = 1/1000 of a sievert

Question 35

How is nuclear radiation used in medicine

Answer 35

* exploring internal organs * controlling/destroying unwated tissue

Question 36

what affects the level of background radiation dose

Answer 36

occupuatioon and location

Question 37

Conditions of exploring internal organs using a tracer

Answer 37

* tracer must emit radiation that can pass out of body and be detected ( gamma/beta) * tracer mustnt be strongly ionising - minimise damage * tracer musnt decay into another radioactive isotope * tracer must have short half life so not present in body for long time

Question 38

what is radiotherapy

Answer 38

cancer detroyed using ionising radiaiton