chapter 7

Question 1

what do you use to detect radioactivity

Answer 1

Geiger-muller tube

Question 2

what are the 3 types of radiation

Answer 2

alpha beta gamma

Question 3

what is alpha radiation made up of

Answer 3

positively charged particles

Question 4

what is the nucleus made up of

Answer 4

protons and neutrons

Question 5

what makes an atom radioactive

Answer 5

unstable nucleus

Question 6

how does an atom get more radioactieve

Answer 6

emitt more alpha beta or gamma

Question 7

what is alpha stopped by

Answer 7

paper

Question 8

does beta go through paper

Answer 8

yes

Question 9

which is the most penetrating form of radiation

Answer 9

gamma

Question 10

what experiment did rutherford carry out

Answer 10

he directed a narrow beam of alpha particles at thin metal foil, some of the particles re bounded back from teh foil, he proved that this happens because each atom has a positively charged nucleus at its centre. He went on to prove that the nucleus contains protons and neutrons

Question 11

who discovered that alpha and beta were made out of differnet particles

Answer 11

ernest rutherford

Question 12

when investigating how thin metal foil scatters a beam of alpha particles why did they do it in a vacumm chamber

Answer 12

prevent air molecules absoribing the alpha

Question 13

in rutherfords experiment how many alpha particles were deflected by more then 90 degreess

Answer 13

1 in 10 000

Question 14

why did the alpha paricles bounce back

Answer 14

because they were posative and so was the protons it was hitting in the nucleus which repelled them

Question 15

what did rutherford conclude from his experiment

Answer 15

there is a posativly charged nucles in the centre of every atom that is :
much smaller then the atom as most particles pass through
where the most mass is located

Question 16

what changes in alpha decay

Answer 16

number of protons and neutrons

Question 17

what changes in beta decay

Answer 17

number of protons

Question 18

what is an isotope

Answer 18

same mumber of protons but differnt number of neutrons

Question 19

what happens to an atom in alpha decay

Answer 19

its mass number goes down by 4 and its atomic number goes down by 2

Question 20

what happens to a atom emitting beta

Answer 20

the mass number stays the same and the atomic number goes up by1

Question 21

what happens to a atom in gamma emission

Answer 21

nothing

Question 22

what is alphas range in air and what is it absorbed by

Answer 22

5cm range in air and is absorbed by thin sheets of paper

Question 23

what is betas range in air and what is it absorbed by

Answer 23

1 m range in air and is absorbed by 2-3mm of lead

Question 24

what is gammas range in air and what is it absorbed by

Answer 24

unlimited range in air and is absorbed by 1m of concrete

Question 25

what is ionisation

Answer 25

when the radiation from a radioactibe substance can knock the electrons out of atoms

Question 26

what is it called when an object is exposed to ionising radiation

Answer 26

irradiated

Question 27

what is radioactive cotammnination

Answer 27

the unwanted presence of materials containing radioactive atoms in other materials

Question 28

which is the most dangerous radiation in the body and why

Answer 28

alpha - the most ionising

Question 29

what is the activity of a radioactive source

Answer 29

the number of unstable atoms in the source that decay per second

Question 30

what is the unit for activity

Answer 30

Bq

Question 31

what is half life

Answer 31

the time it takes for activity to half

Question 32

how do radioactive tracers work

Answer 32

They are used to trace the flow of a substance through an organ. The tracer contains a radioactive isotope that emits gamma radiation. Before the test the patient would drink water with a small amount of radiation, a detector is then placed against each kidney, the substance would flow in and out of a normal kidney so the detector would go up then down , for a blocked kidney the reading would go up and stay up.

Question 33

what happens in fission

Answer 33

the nuclues of an atom is struck by a neutron, causing the nucleus to split into 2 smaller fragment nuclei and release neutrons

Question 34

what does fission release

Answer 34

2 or 3 neutrons , energy in the form of gamma radiation + kinetic energy

Question 35

what does water do in a fission reacter

Answer 35

acts as a moderator as it slows down the fission neutrons

Question 36

how does fusion work

Answer 36

2 small nuclei are fused together to form a single larger nucleus