3. Radiation / Nuclear decay

Question 1

What is Rutherfords alpha scattering experiment

Answer 1

The first time where scientists found the new atomic diagram / structure of particles

Question 2

What is an alpha particle

Answer 2

A helium nucleus that is highly ionising and cannot penetrate through paper

Question 3

What is a beta particle

Answer 3

Very fast electron that is medium ionising and can be stopped by thin steel

Question 4

What are gamma particles

Answer 4

High energy photons of em radiation that can only be stopped by thick lead

Question 5

What is background radiation

Answer 5

Radiation that occurs naturally from surroundings

Question 6

Give examples of back ground radiation

Answer 6

Cosmic rays
Medical equipment
Radon gas
Food

Question 7

What is activity

Answer 7

The number of decays taken place per second

Question 8

Units of activity

Answer 8

Becerquels (Bq)

Question 9

What is a Bq

Answer 9

A single decay of a nucleus per second

Question 10

What is half life

Answer 10

The amount of time taken for half the radioactive nuclei to decay.
The time taken for the number of radioactive nuclei to become half

Question 11

What does it mean by spontaneous

Answer 11

When an atom or nucleus decays without any trigger such as heat or light ect… it is unprovoked

Question 12

Half life equation

Answer 12

T½ = ln2 / Y

Y = decay constant

Question 13

activity equation

Answer 13

A = - Y x N

Question 14

Name two applications of radioactivity

Answer 14

Tracers = finding leaks in pipes
Carbon dating
Medical = MRI, radio therapy

Question 15

what is the difference between irradiation and contamination

Answer 15

Irradiation is the process by which an object is exposed to radiation, including radiation from the nuclei of atoms

Contamination is if the object has been introduced to a radioactive material eg on clothing or skin

Question 16

How is radiation hazardous?

Answer 16

Radiation can cause cell mutation and uncontrolled cell growth
It ionizes cells
If exposed to high dosages of radiation then cells can be damaged faster then they are replaced causing radiation sickness and poisoning

Question 17

Example of misuse of radioactive material

Answer 17

Alexander Litvineko - poisoned with polonium isotope 210 which emits alpha radiation causing him to die of radiation sickness

Question 18

definition of nuclear binding energy

Answer 18

The energy released when a nucleus forms = the work done in separating a nucleus into atoms

Question 18

Why is radon gas particularly dangerous

Answer 18

It is very dense so when released from rocks it settles at lower levels meaning in an area of houses with radon rocks, basements can be filled with radioactive gases unknowingly.
It is highly ionising and can also contaminate water supplies and wells

Question 18

How does gamma radiation interacts with matter

Answer 18

The photoelectric effect

Question 19

definition of mass defect

Answer 19

the difference in mass from when it is before then after it is formed

Question 20

what is the equation that related energy to mass

Answer 20

e = mc^2

Question 21

what is the most stable element

Answer 21

iron

Question 22

what is the atomic mass unit

Answer 22

1 u = 1.66 x10 ^-27

Question 23

What is the binding energy per nucleon

Answer 23

the amount of binding energy / the nucleon number

Question 24

What are the different sides of a MeV- Nucleon number graph

Answer 24

to the left of iron = fusion (they are smaller particles needing to be binded together) to the right of iron = fission (they are larger particles that are separated)

Question 25

What is the differences between fission and fusion?

Answer 25

fission: always have neutrons produced , Splits up atoms , generated electricity , has a chain reaction fusion: joins up atoms, needs to overcome repulsion , uses high pressure and high speeds for the reaction

Question 26

What are the components of a nuclear reactor

Answer 26

control rods coolant moderator fuel pods /elements

Question 27

what is the purpose of the control rods

Answer 27

used to control the rate of fission to stop the reactor from overheating and causing a core meltdown. they absorb all but one neutron stopping the chain reaction from continuing.

Question 28

How does the release of nucleons lead to a chain reaction

Answer 28

The neutrons released will be absorbed by other element nuclei , these will then split producing more neutrons, these will then be absorbed and the process continues

Question 29

what is the conservation of mass energy

Answer 29

mass can be converted to energy using einsteins equation so the amount of mass and energy is constant even if there is a change in mass e=mc^2

Question 30

What things are conserved in a nuclear reaction

Answer 30

the nucleon number the proton number mass - energy momentum

Question 31

how do each of the radioactive particles react in a magnetic field?

Answer 31

Force in electric field = Eq Magnetic force = Bvq Alpha particle = +2e charge = little force = big mass = no deflection Beta particle = -1e charge = half forces of a = little mass = larger deflection Gamma particle = no charge = no deflection

Question 32

Why is energy released in reactions on a fission/fusion graph?

Answer 32

The energy released comes from the reduction in mass as it is converted into energy E=mc^2

Question 33

Give a benefit and issue of a nuclear power plant

Answer 33

It creates clean energy as no greenhouse gases are released. However the area could suffer radioactive poisoning if there was a core meltdown.

Question 34

Why are velocitys hard to measure when there is a red shift?

Answer 34

The distortion of light waves is less as it is not travelling fast so the increase in detected frequency is very small. This is harder to then detect and measure.

Question 35

How does conservation of energy apply to an elliptical orbit?

Answer 35

KE is released as it travels round. The PE increases as the KE increases. Keplers 2nd Law

Question 36

What is the top number next to an element on the periodic table

Answer 36

The mass number = the number of protons and neutrons combined

Question 37

What is the bottom number next to an element on the periodic table

Answer 37

The Atomic number so the number of protons or the number of electrons

Question 38

How to derive the decay constant equation:

Answer 38

Use t = T1/2 and N/N0 = 1/2 N/N0 = e^-Yt Substitute in values