radiation

Question 1

what is alpha radiation?
what particles does it consist of?
what is its charge?
what is it blocked by?
ionising strength?
penetrating strength?

Answer 1

alpha radiation is a helium nucleus and consists of 2 protons and 2 neutrons giving a positive charge. It is blocked by a sheet of paper or a few cm of air and its ability to ionise is strong but it’s penetration power is weak.

Question 2

what is beta radiation?
what particles does it consist of?
what is its charge?
what is it blocked by?
ionising strength?
penetrating strength?

Answer 2

beta is a fast moving electron which is ejected from a nucleus of an atom when a neutron splits into a proton and electron. It has a negative charge. It is blocked by about 3mm of aluminium and its ability to ionise is weak

Question 3

what is gamma radiation?
what particles does it consist of?
what is its charge?
what is it blocked by?
ionising strength?
penetrating strength?

Answer 3

Gamma has no charge as it is part of the electromagnetic spectrum it has a very short wavelength and very high energy. It is blocked by about 3 cm of lead and its ability to ionise is weak and it’s penetration power is high.

Question 4

what is ionisation?

Answer 4

Ionisation occurs when an atom gains or loses electrons to become charged

Question 5

what is decaying

Answer 5

A radioactive source contains unstable nuclei that decay to more stable forms by emitting radiation

Question 6

what is activity?

Answer 6

the number of decays per second

Question 7

what is half life?

Answer 7

the half life of a radioactive source is the time taken for the activity of the source to decrease to half of its original value or the time taken for half the nuclei in a source to decay

Question 8

absorbed dose equation

Answer 8

absorbed dose = energy absorbed / mass of tissue

D=E/M

Question 9

equivalent dose equation

Answer 9

equivalent dose (sv) = absorbed dose (Grays) X radiation weighting factor
H=DWr

Question 10

what is the average annual background radiation in the UK?

Answer 10

2.2msv

Question 11

what is the average effective does limit for a member of the public?

Answer 11

1msv

Question 12

what is the average effective dose limit for a radiation worker?

Answer 12

20 msv

Question 13

what happens during nuclear fission?

Answer 13

a neutron is fired at a large, unstable nucleus splitting the nucleus in two and releasing heat energy and more neutrons

Question 14

what is a chain reaction?

Answer 14

the neutrons released from a fission reaction go on to split other nuclei and the process continues

Question 15

nuclear power

Answer 15

we can use energy stored in atomic nuclei to generate power by using two different reactions

Question 16

how do nuclear reactions work?

Answer 16

nuclear reactions produce heat which is used to boil water into steam. The steam turns a turbine which spins a generator producing electricity.

Question 17

what is the energy change during a nuclear reaction?

Answer 17

nuclear - heat - kinetic - electrical

Question 18

what is nuclear fusion?

Answer 18

two small nuclei fuse together to form a larger nucleus

Question 19

what is one gray equal to?

Answer 19

One gray is equal to one joule per kilogram

Question 20

is heat released during fission?

Answer 20

yes

Question 21

equivalent does rate formula

Answer 21

H*= H/t
equivalent does rate = equivalent dose÷ time

Question 22

what is weighting factor related to?

Answer 22

ionising strength

Question 23

what is the order of particles in a nucleus in increasing size ?

Answer 23

electron, proton, helium nucleus

Question 24

How does radiotherapy with gamma rays work?

Answer 24

gamma radiation has such high energy it can kill live cells

Question 25

name 2 advantages of nuclear fission

Answer 25

• Nuclear reactors do not produce pollutants
• The fuel for nuclear reactors will last a long time

Question 26

name 2 disadvantages of nuclear fission

Answer 26

Nuclear reactors are expensive to build and the time from deciding to build one and it being operational can be many years
*Leaks of radioactive materials can have a major impact on the surrounding environment
*Waste from nuclear reactors must be stored underground for a long time until the radiation emitted decreases.

Question 27

precautions to take to avoid absorbing radiation

Answer 27

lift radioactive sources with forceps
wear a lead vest
distance yourself from the radioactive material
do it quickly

Question 28

what can nuclear radiation be used for medically and industrially?

Answer 28

used to treat tumors by killing the cancer cells present in a tumour.

can sterilise medical instruments by destroying organisms on them

radiation can be concentrated in certain organs in the body and this helps a doctor to diagnose or treat a disease.

used in some detectors

Question 29

background radiation?

Answer 29

man made :
building materials
radioactive materials used in smoke detectors

natural :
cosmic radiation from outer space
rocks and minerals like granite.

Question 30

what does an atom consist of?

Answer 30

protons, neutrons and orbiting electrons