Physics Topic 4

Question 1

Describe the process of nuclear fission (4)

Answer 1

A neutron is absorbed by a large nucleus
The nucleus splits into two smaller nuclei
This releases energy and two or three neutrons

Question 2

What’s the definition of activity

Answer 2

Overall rate of decay of all the isotopes in our sample

Question 3

Unit of activity

Answer 3

Becquerels (Bq)

Question 4

1 Bq = what

Answer 4

1 decay per second

Question 5

Half life definitions

Answer 5

1. Time taken for the number of radioactive nuclei in a sample to half
2. Time taken for the number of decays to half

Question 6

How is activity measured

Answer 6

Geiger muller tube and counter

Question 7

How does the Geiger muller tube work

Answer 7

Records all the decays that reach them each second as a count rate

Question 8

2 uses of radiation inside the body

Answer 8

Radiotherapy and medical tracers

Question 9

What happens to cells if they receive too much radiation

Answer 9

They die

Question 10

Major problem of ionising radiation inside the body

Answer 10

It can mutate DNA which can cause cancer

Question 11

What can happen if you receive large doses of radiation

Answer 11

Radiation sickness
Including vomiting, tiredness, hair loss

Question 12

What’s the treating of cancer called with radiation

Answer 12

Radiotherapy

Question 13

What are the two ways radiation can be delivered

Answer 13

Externally or internally

Question 14

What’s the external method of delivering radiation

Answer 14

Emit gamma rays targeted at cancer site at lots of different angle

Question 15

What’s the internal method of radiation therapy

Answer 15

Place the radioactive source either inside the cancer or next to the cancer

Question 16

What radiation type is best for internal radiation therapy

Answer 16

Beta radiation which is more damaging than gamma but can’t pass as far through the body

Question 17

Sides effect of radiotherapy

Answer 17

Healthy cells are damaged or killed

Question 18

How do medical tracers work

Answer 18

They track movements of isotopes around the body to see if particular organs are working properly

Question 19

What radiation is used for tracers

Answer 19

Gamma

Question 20

What does radioactive mean

Answer 20

Consists of unstable isotopes that can decay

Question 21

What are alpha particles made up of

Answer 21

2 protons and 2 neutrons (helium atom)

Question 22

Alpha charge

Answer 22

2+

Question 23

Penetration of alpha

Answer 23

Can’t penetrate very far- few cm- absorbed by paper

Question 24

How ionising is alpha

Answer 24

Very strongly

Question 25

Beta charge

Answer 25

-1

Question 26

How ionising are beta particles

Answer 26

Moderately ionising

Question 27

Penetration of beta particles

Answer 27

Moderately far - several metres - 5 mm of aluminium

Question 28

What are gamma rays

Answer 28

Waves of electromagnetic radiation (often emitted after alpha or beta radiation)

Question 29

How ionising are gamma rays

Answer 29

Weak because they have no mass or charge

Question 30

Penetration of gamma rays

Answer 30

Really far - thick sheets of led

Question 31

Irradiation meaning

Answer 31

The process by which an object is exposed to radiation

Question 32

Contamination meaning

Answer 32

When radioactive particles get onto other objects

Question 33

What determines how harmful radiation is

Answer 33

Where you’re exposed to it Type of radiation The amount of

Question 34

What’s the most dangerous radiation outside the body

Answer 34

Gamma and beta

Question 35

What’s the most dangerous radiation inside the body

Answer 35

Alpha

Question 36

Three things dosage depends on

Answer 36

How far away from the source you are How long you are exposed to it How radioactive that substance is

Question 37

Precautions to minimise irradiation and contamination

Answer 37

Wearing protective gear (gloves and overalls) Handling radioactive items with tools Keep item in lead-lined box

Question 38

Pros and cons of nuclear energy

Answer 38

Pros - uranium or plutonium fuel is relatively cheap -produces a large and steady amount of energy -clean energy Cons -nuclear power plants are expensive to build -Nuclear waste is expensive to get rid of -risk of major disaster

Question 39

What’s the relative mass of protons and neutrons

Answer 39

1

Question 40

What does atomic number show

Answer 40

How many protons there is in

Question 41

What does mass number show (top number)

Answer 41

Total number of protons and neutrons

Question 42

How do you know how many electrons are in an elements

Answer 42

Atomic number (same amount as protons)

Question 43

What’s an isotope

Answer 43

Atoms with the same number of protons but different numbers of neutrons

Question 44

How does an electron move energy levels

Answer 44

If they gain enough energy from electromagnetic radiation the electron becomes ‘excited’

Question 45

What happens after an electron falls back down an energy level?

Answer 45

It will remit energy as electromagnetic radiation

Question 46

In what order were the subatomic particles found in

Answer 46

Electron, proton, neutron

Question 47

What order was the atomic models

Answer 47

Solid sphere Plum pudding Nuclear Planetary

Question 48

What did John Daltons model and when

Answer 48

Solid sphere model 1803

Question 49

What was J.J Thompson model and when

Answer 49

Plum pudding model 1904

Question 50

What’s was Rutherford model and when

Answer 50

Nuclear 1911

Question 51

What was Neil Bohrs model and when

Answer 51

Planetary 1913

Question 52

Process of nuclear fusion (3)

Answer 52

Light nuclei Join to form a heavier nuclei Some of the mass of the nuclei is converted to energy f

Question 53

Where does nuclear fusion happen

Answer 53

Inside stars