Term 2 Part 3 - Radiation

Question 1

what is an isotope?

Answer 1

Atoms of the same element (same number of protons) with different mass numbers/amount of neutrons

Question 2

what are radioisotopes?

Answer 2

Atoms that have unstable nuclei (eject particles/electromagnetic waves or undergo nuclear decay)

Question 3

what are 3 factors that make the nucleus unstable?

Answer 3

• Protons can experience electrostatic forces that can make them repel
• A strong nuclear force is needed to keep the protons and neutrons in the nucleus
• Neutrons help to reduce the repulsion between the protons
• Too many neutrons compared to protons
• Nucleus too big

Question 4

what is radioactivity?

Answer 4

natural decay of unstable nuclei which releases radiation

Question 5

what is irradiation?

Answer 5

intentional exposure of something to radiation WITHOUT making it radioactive

Question 6

what is nuclear decay?

Answer 6

Protons and neutrons in the nucleus are constantly moving and rearranging themselves which sometimes causes the nucleus to emit high energy electromagnetic radiation and can cause the article to chnage into a differet element.

Question 7

what is the relationship between nuclear decay and radiation?

Answer 7

The activity of a radioactive source is the rate at which it decays

Question 8

what is count rate?

Answer 8

the count rate is the number of decays per second recorded by a detector

Question 9

what is radioactivity measured with?

Answer 9

radioactivity is measured with a geiger counter

Question 10

what are the 3 types of radiation?

Answer 10

alpha, beta, gamma

Question 11

what does an alpha particle contain?

Answer 11

2 protons 2 neutrons

Question 12

what is an alpha particle emitted from?

Answer 12

Emitted from A NUCLEUS THAT IS TOO BIG

Question 13

what is the alpha particle symbol?

Answer 13

Question 14

what does a beta particle contain?

Answer 14

1 electron

Question 15

what is a beta particle emitted from?

Answer 15

Emitted from A NEUCLEUS WITH TOO MANY NEUTRONS

Question 16

what does a beta particle split into?

Answer 16

Splits into 1 proton and 1 electron

Question 17

what is the beta particle symbol?

Answer 17

Question 18

what is different about gamma from beta and alpha?

Answer 18

it is a ray, not a particle

Question 19

when are gamma rays emitted?

Answer 19

EMITTED DURING NUCLEAR DECAY

Question 20

what are 4 properties of alpha particles?

Answer 20

• Strong ionizing power
• because of its 2+ charge it can attract electrons of their electron shells in their atom which can cause the atom to change because the number of electrons changes
• deflects towards NEGATIVELY charged plates/objects
• weakest penetration power

Question 21

what are 4 properties of beta particles?

Answer 21

• Weaker ionizing power than alpha
• because of its 1- power it needs to come closer the the electron shells in order to REPEL the electron (so the electron leaves the shells but it doesn’t attract towards the beta particles instead it goes the other way because it is repelled)
• deflects towards POSITIVELY charged plates/objects because of its negative charge
• slightly stronger penetration power than alpha

Question 22

what are 4 properties of gamma rays?

Answer 22

• Weakest ionizing power
• its 0 charge means it has to directly hit the electron in order to knock it off the shells which is rare and hard to do
• undeflected by charged plates/objects because it has no charge
• strongest penetration power

Question 23

what is the definition of ionising?

Answer 23

particles or waves that cause atoms to lose or gain electrons and become charged

Question 24

what can alpha, vs beta vs gamma penetrate through?

Answer 24

Question 25

what are gamma rays usually used for?

Answer 25

Gamma is usually used to sterilize objects, or used in radiation detection in the body because it has the highest penetration rate so it is easily able to leave objects or the body

Question 26

what are the formulas for alpha vs beta vs gamma?

Answer 26

Question 27

what is half life?

Answer 27

the time it takes for half the sample to decay

Question 28

what are 7 ways radiation is used in daily life?

Answer 28

- Automatic thickness monitoring - Smoke detectors -Medical tracers - Carbon dating - Uranium dating - Killing cells - Fault Tracers

Question 29

how does automatic thickness monitoring work?

Answer 29

If the material is too thick, more radiation is absorbed so less shows through to the other side If the material is too thin, less radiation is absorbed so more shows through to the other side

Question 30

what type of particles are used for automatic thickness monitoring and why?

Answer 30

Beta particles are used because they are able to pass through the materials and be detected properly

Question 31

what does the automatic thickness detector detect?

Answer 31

The detector detects the amount of radiation and adjusts how far apart the rollers are to change the thickness

Question 32

how do medical tracers work?

Answer 32

The parts where there is less radiation show there could be something blocking it from travelling around the body

Question 33

what radiation particles are used for medical tracers and why?

Answer 33

Beta or gamma is used because it can pass out and in of the body really easily

Question 34

how does carbon dating work?

Answer 34

Carbon-14 can decay but Carbon-12 cannot. It compares the ratio of Carbon-14 to Carbon-12 to see what the half-life is to determine the age. When an organism dies, C-14 levels decrease and decay into Nitrogen-14

Question 35

how does uranium dating work?

Answer 35

Uranium decays into lead. We measure the ratio of uranium to lead in the rock. We use the ½ life of uranium to estimate how long ago the rock formed

Question 36

how does killing cells work?

Answer 36

Gamma rays used at high frequency and precisely directed to kill cells

Question 37

why are gamma rays used to kill cells

Answer 37

Gamma used to kill cells because high penetration and low ionization

Question 38

how do smoke detectors work?

Answer 38

Contains radioactive substance which ionizes air causing current to flow. The smoke particles enter neutralising ions which decreases/stops currentand causes the alarm.

Question 39

what particle is used for smoke detectors and why?

Answer 39

Alpha used because it has low penetration but high ionization

Question 40

how do fault tracers work?

Answer 40

Radiation is put through a pipe and radiation detectors are put outside the pipe. This then tracks the radiation escape through amount changing.

Question 41

what rays/particles are used for fault tracers and why?

Answer 41

Gamma can penetrate & leave pipes