Radioactivity

Question 1

What is radioactivity

Answer 1

The phenomena in which nuclei emitt particles and energy randomly and sponteniously in order to attain stability

Question 2

How does the nucleus of an isotope try to become stable

Answer 2

It will try to lose neutrons in the form of radiation

Question 3

Why is radioactivity random?

Answer 3

Any atom out of millions could be unstable and start to lose neutrons in the form of radiation

Question 4

Why is radioactivity spontenious?

Answer 4

It isn’t affected by physical factors such as temperature, pressure and catalysts

Question 5

What is the name given to naturally occuuring radiation from the environment?

Answer 5

Background radiation

Question 6

Why is air radioactive?

Answer 6

It contains radon gas

Question 7

What are other sources of background radiation?

Answer 7

The ground, food and drink, living things, cosmic rays from sun

Question 8

What are artificial sources of radiation?

Answer 8

Medical equipment, nuclear weapons, X-rays and Gamma rays used in hospitals

Question 9

Who discovered radioactivity?

Answer 9

Henri Becquerel

Question 10

Why isn’t photographic paper the best way to detect radioation?

Answer 10

It won’t tell you the magnitude of radiation

Question 11

What is the most efficient way to detect radiation?

Answer 11

The Geiger Muller (GM) tube / counter

Question 12

What is radioactive decay?

Answer 12

The process through which radioactive atoms change into to orher elements

Question 13

What is an alpha particle similar to?

Answer 13

A helium nucleus

Question 14

What is the composition of an alpha particle?

Answer 14

Two protons, two neutrons

Question 15

What is the charge on an alpha particle?

Answer 15

+2

Question 16

Why is alpha the slowest radiation?

Answer 16

It is the heaviest

Question 17

What happens when an atom releases an alpha particle?

Answer 17

Mass number decreases by 4, proton number decreases by 2

Question 18

What is a beta particle?

Answer 18

An electron

Question 19

What happens during a beta decay?

Answer 19

A neutron changes in to a proton and an electron. The electron leaves, so that mass number stays the same but proton number increases by 1

Question 20

Why is a beta particle fast?

Answer 20

It has no mass

Question 21

What is gamma?

Answer 21

Electromagnetic radioation

Question 22

When is gamma released

Answer 22

At the same time as the alpha or beta particle

Question 23

What two types of energy come from radioactive substances?

Answer 23

Kinetic and electromagnetic

Question 24

Why is alpha the least penetrating?

Answer 24

It is stopped by paper

Question 25

What is needed to stop beta?

Answer 25

A few mm of aluminium / glass / concrete / 1m of air

Question 26

What is needed to stop gamma radiation?

Answer 26

2cm or more of lead

Question 27

What is ionisation?

Answer 27

The formation of ions when electrons leave or are gained

Question 28

WHy is gamma the least ionising?

Answer 28

It is the fastest radiation. It moves too fast to knock off an electron

Question 29

Why is alpha most ionising?

Answer 29

It is slow and heavy It has a greater volume so there is more chance of a collision It has more energy and a larger charge

Question 30

How do alpha and beta particles behave in electric fields?

Answer 30

Alpha deflects towards the negative plate and beta towards the positive plate

Question 31

How do alpha and beta behave in magnetic fields?

Answer 31

Alpha is delfected towards south. Beta is deflected towards north

Question 32

Why aren't gamma rays affected by magnetic or electric fields?

Answer 32

They have no charge and aren't deflected.