TOPIC 4

Question 1

What does a change of state require

Answer 1

Energy

Question 2

Why are there flat spots on the heating graph

Answer 2

Energy is being transferred by heating but not being use to change the temperature

Question 3

When melting and boiling a substance energy is getting put in what the energy used for

Answer 3

Breaking intermolecular bonds rather than rising the temperature

Question 4

What is the energy needed to change state of substance

Answer 4

Latent heat

Question 5

When a substance is condensing or freezes bonds form between the particles
What energy is released

Answer 5

The internal energy decreases

Question 6

What is specific latent heat of a substance

Answer 6

The amount of energy needed to change 1kg of it from one state to another without changing its temperature

Question 7

When a substance cools what is the SLH

Answer 7

The energy is released by a change in state

Question 8

Is specific latent heat the same for every substance

Answer 8

It is different for different materials and for changing between different states

Question 9

What is the specific latent heat for changing between solid and liquid (melting and freezing)

Answer 9

The specific latent heat of fusion

Question 10

What is the specific latent heat for changing between a liquid and gas (evaporating, boiling or condensing)

Answer 10

It is the specific latent heat of vaporisation

Question 11

What is the formula for when a substance changes

Answer 11

Energy (E) = mass (m) x specific latent heat (L)

Energy is given in joules (j) mass is in kg and SLH is in j/ kg

Question 12

What three radioactive substances of ionising radiation from their nuclear

Answer 12

Alpha, beta and gamma radiation

Question 13

What is ionising radiation

Answer 13

Radiation that knocks electrons off atoms, creating positive ions. The ionising power of a radiation source is how easily it can do this

Question 14

What is alpha radiation

Answer 14

It is when alpha particles is emitted from the nucleus and a-particles is two neutrons and two protons

Question 15

What are alpha particles

Answer 15

Helium Nucluei

Question 16

What are beta particles

Answer 16

Is a simply a fast- moving electron released by the nucleus. But beta particles have virtually no mass and a charge -1.

Question 17

What type of ions are alpha and beta

Answer 17

Alpha are strongly ionising and beta particles are moderately ionising they penetrate moderately far into materials before colliding

Question 18

When is a neutron in the nucleus has turned into a proton

Answer 18

For every beta particles emitted

Question 19

What are Gemma rays

Answer 19

They are waves of electromagnetic radiation released by the nucleus

Question 20

What do gamma rays do

Answer 20

Penetrate far into materials without being stopped and will travel a log distance through air. They collide with atoms. Eventually they hit something and do damage

Question 21

What can gamma rays be absolutely by

Answer 21

Thick sheets of lead or metres of concrete

Question 22

What does a nuclear equation show

Answer 22

Radioactive decay by using element symbols

Question 23

What are radioactive decay written like

Answer 23

Atom before decay ➡️ atom after decay + radiation emitted.

Question 24

What is the golden rule to remember

Answer 24

The total mass and atomic numbers must be equal on both sides

Question 25

How any protons and neutrons are alpha particles made from

Answer 25

2

Question 26

How does an alpha decay decreases the charge and mass of the nucleus

Answer 26

A proton is positively charged and a neutron is neutral, so the charge of the nucleus decreases and

Question 27

What are gamma rays used for

Answer 27

They are a way of getting rid of excess energy from the nucleus This means that there are no change to the atomic mass or atomic number of the atoms

Question 28

What do radioactive substances give out

Answer 28

A radiation from the nuclei of their atoms- no matter what

Question 29

What is the radiation measured in

Answer 29

With a Geiger- Müller tune and counter which records the count-rate

Question 30

What is the half-life

Answer 30

The amount of radiation emitted by a source to halve, this is known as the half-life

Question 31

Why do we use the idea of half-life

Answer 31

The problem with trying to measure this is that the activity never reaches zero, which is why we have to use the idea of half- life to measure how quickly the activity drops off

Question 32

What can half-life be described as

Answer 32

As the time taken for the activity to fall to half of its initial value

Question 33

How can half-life be measured from

Answer 33

By using a graph

Question 34

How is the half life found on a graph

Answer 34

Time internal on the bottom axis corresponding to a having of the activity on the vertical axis

Question 35

What damage can ionising do

Answer 35

They can enter living cells and ionise atoms within them. This can damage the cells (cancer) it kill them off completely so it’s important to know the precautions to take when taking when working with any sources of radiation

Question 36

How are objects near a radioactive source

Answer 36

They are irradiated by it. This means they are exposed to it

Question 37

How can the effect of irradiation be reduced

Answer 37

Keeping sources in lead-lined boxes and standing behind Barrie’s when using sources are common ways of reducing the effects of irradiation

Question 38

How else is radiation kept controlled

Answer 38

The source may be in a different room and remote-control arms are used to handle it

Question 39

How are objects contaminated from radioactive particles

Answer 39

Unwanted radioactive atoms get onto or into an object, the object is said to be contaminated

Question 40

When you contaminated how dangerous it is

Answer 40

Because radioactive particles radiation could cause you harm

Question 41

What can be done so a person doesn’t get contaminated

Answer 41

Gloves and tongs should br used when handling sources to avoid particles getting stuck to your skin or under your nails Protective suits to stop then breathing in particles

Question 42

How are beta and gamma sources dangerous

Answer 42

They can penetrate the body and get to delicate organs

Question 43

How is alpha less dangerous

Answer 43

Because it does penetrate the skin and is easily blocked by a small air gap

Question 44

Which type of radiation is more concerning

Answer 44

Alpha

Question 45

How are alpha source are more dangerous inside the body

Answer 45

Because they damage in a very localised area. So contamination, rather irradiation

Question 46

Why is it important that we have a better understanding of the different radiation affecting our bodies

Answer 46

They better we an protect ourselves when using them. The data is peer-reviewed and can quickly become accepted