radioactivity

Question 1

What is the Rutherford experiment

Answer 1

He fired neutrons at gold film in order to test whether the plum-pudding model was correct

Question 2

What was the outcome of the Rutherford experiment

Answer 2

If the plum-pudding model was correct the neutrons would have passed straight through ,however, some deflected at an angle and others were repelled

Question 3

what was the plum-pudding model

Answer 3

Electrons with a negative charge were surrounded by a cloud of positive electric charge

Question 4

What is alpha decay

Answer 4

The parent nucleus emits 2 protons and 2 neutrons(which is a helium nucleus)

Question 5

What are the products of alpha decay

Answer 5

The daughter nucleus has 4 less nucleons and 2 less protons. It produces an alpha particle which has 4 nucleons and 2 protons

Question 6

What is beta decay

Answer 6

A reaction in the parent nucleus producing an electron

Question 7

what are the products of beta decay

Answer 7

The daughter nucleus has 1 more proton whilst the nucleons stay the same. A beta particle is produced which is just 1 electron.

Question 8

what is gamma decay

Answer 8

an electromagnetic wave is emitted causing the nucleus to lose energy

Question 9

What are the products of gamma decay

Answer 9

There are no changes

Question 10

Alpha particle stats

Answer 10

mass number of 4, 2+ charge, low penetrating power and a high ionising ability, speed is slow

Question 11

Beta particle stats

Answer 11

negligible mass number, 1- charge, moderate penetrating power and a moderate ionising ability, speed is fast

Question 12

Gamma particle stats

Answer 12

mass number of 0, charge of 0, high penetrating power and a low ionising ability, travels at the spead of light 3x10^8 m/s

Question 13

What is half life

Answer 13

The time taken for;

• number of radioactive nuclei to halve
• mass to halve
• activity to halve

Question 14

How to measure half-life on a graph

Answer 14

You need an average of three intervals being exactly half of the value of the one previous to it and then measure the time taken between the three. They should take the same time to half if half life is occurring

Question 15

Leak detection

Answer 15

They emit gamma rays due to it’s long range and high penetrating power so it can detect the leakage the best

Question 16

Tracing movements

Answer 16

Scientists are able to know where and how fast water could be travelling when iridium-113 is injected into it at very small dosages as scientists can look at the gamma radiation given off from it.

Question 17

why can beta or gamma be used in medical tracing but not alpha?

Answer 17

beta or gamma will pass out the body quickly, however, alpha would most likely be absorbed and is very ionising so it can be deadly

Question 18

why is half life important in radioactive tracing

Answer 18

must be long enough to follow the investigation and yet short enough to avoid unnecessary exposure

Question 19

Why is gamma radiation used in radiotherapy

Answer 19

Gamma is penetrating enough that it is able to enter the body to then kill the cancer cells, it is also not very ionizing so it won’t be as harmful to the body as beta or alpha

Question 20

why are alpha particles not used in smoke alarms

Answer 20

they are not penetrating enough and are likely to be absorbed by the smoke itself

Question 21

what type of radiation is used to sterilize medical equipment and food

Answer 21

gamma

Question 22

why is gamma used to sterilize medical equipment and food

Answer 22

it destroys the bacteria and the energy of gamma rays passes through the equipment, disrupting the pathogens that cause contamination

Question 23

why is beta used in thickness control

Answer 23

Beta is able to penetrate paper ,however, this penetration starts to vary as the thickness of the paper changes. It can monitor the thickness of the paper

Question 24

What is nuclear fission

Answer 24

A neutron is slowly fired at a parent nuclei which then splits into two daughter nuclei and produces lots of energy

Question 25

What is a chain reaction

Answer 25

Where one fission causes many more fission events which then lead to more fission events in an uncontrollable fashion

Question 26

what is a turbine

Answer 26

A windmill like mechanism which gets turned by the steam from the reactor to generate energy

Question 27

what is nuclear fusion

Answer 27

a reaction in which two or more atomic nuclei are combined to form one or more different atomic nuclei and subatomic particles

Question 28

what is the life cycle of low and medium mass stars

Answer 28

nebula => main sequence => red giant => “planetary nebular” => white dwarf

Question 29

what is the life cycle of high-mass stars

Answer 29

nebula => main sequence => red supergiant => supernova => neutron star

Question 30

what is the life cycle of very high-mass stars

Answer 30

nebula => main sequence => red supergiant => supernova => black hole

Question 31

what is the function of the control rods

Answer 31

used to absorb excess neutrons and prevent chain reaction

Question 32

what is the function of a moderator

Answer 32

substance (usually water or CO2) used to absorb energy from the nuclear reactor to generate electricity

Question 33

what is the function of a coolant

Answer 33

slows down neutrons in the reactor to ensure they are able to interact with Uranium

Question 34

what is the function of the fuel rods

Answer 34

contains the uranium needed for the reactor