Radio Active Emissions

Question 1

What is an isotope?

Answer 1

An isotope is an atom with the same number of protons and electrons but a different amount of neutrons

Question 2

The nucleus of unstable atoms will …

Answer 2

Emit radiation

Question 3

What is alpha radiation?

Answer 3

Alpha radiation is the nucleus of a helium atom

Question 4

What is beta radiation?

Answer 4

A fast moving electron

Question 5

What is gamma radiation?

Answer 5

A wave of the electromagnetic spectrum

Question 6

What is neutron radiation?

Answer 6

A neutron from the nucleus

Question 7

Where does the bats particle come from?

Answer 7

Neutrons are not stable they can decay to give out a proton and an electron

Question 8

How do you detect radiation?

Answer 8

With a Geiger counter it clicks when radiation enters it. Each click is a tiny current produced when the radiation ionised the gas inside the tube

Question 9

What would stop alpha radiation?

Answer 9

A few sheets of paper, skin, a few cm of air

Question 10

What would stop beta radiation?

Answer 10

A few mm of aluminium

Question 11

What would stop gamma radiation?

Answer 11

A few cm of lead or a meter of concrete

Question 12

Put gamma, alpha and beta radiation in order from smallest to largest penetrating power

Answer 12

Alpha, beta, gamma

Question 13

What type of radiation is emitted by a radioactive material?

Answer 13

Ionising radiation

Question 14

What does ionising radiation do to atoms?

Answer 14

The radiation can remove electrons from atoms to produce positively charged ions

Question 15

What is the relative mass of the types of radiation?

Answer 15

Alpha - large, beta - small, gamma - none

Question 16

What is the charge of the three types of radiation?

Answer 16

Alpha +2, beta -1, gamma none

Question 17

What is the ionising power of the three types of radiation?

Answer 17

Alpha high, beta medium, gamma low

Question 18

What is the range of the three types of radiation?

Answer 18

Alpha short, beta medium, gamma long

Question 19

Why do alpha particles have a short range?

Answer 19

You have to transfer energy to an atom to ionise it. Alpha particles transfer more energy to the material they are travelling through than gamma rays this is why they have a much shorter range

Question 20

What happens in alpha decay?

Answer 20

Large nuclei are unstable. Two protons and two neutrons can join up to form an alpha particle which is emitted from the nucleus

Question 21

What happens in beta decay?

Answer 21

In beta decay a neutron decays to a proton and an electron. The electron is emitted as the beta particle. The number of neutrons goes down by one but the number of protons goes up by one. The charge in the nucleus increases by +1

Question 22

What happens in gamma decay?

Answer 22

Gamma rays are electromagnetic rays, so don’t have mass or charge. When a nucleus emits a gamma ray the mass and atomic numbers stay the same. Gamma rays are often given off along side alpha or beta decay

Question 23

What happens in neutron emission?

Answer 23

When some nuclei decay they produce nuclei with large numbers of neutrons. These nuclei can emit neutrons

Question 24

Why when listening to a Geiger counter does it not click at regular intervals?

Answer 24

This is because the material doesn’t emit radiation in a regular pattern it is random

Question 25

What does a Geiger counter measure?

Answer 25

The radiation emitted per second. This is called activity, or count rate and is measured in becquerels Bq. One Bq is one count per second

Question 26

What is half life?

Answer 26

The activity of a radioactive material decreases with time. The time it takes activity to half is called the half life. A half life can be very long or short. The atoms that decay do not disappear they emit alpha and beta particles until they turn into a more stable element

Question 27

Electrons are negative and the nucleus is positive so why do the electrons not spiral into the nucleus ?

Answer 27

Because they can only occupy certain energy levels

Question 28

What is the photon model of electromagnetic radiation?

Answer 28

In the photon model electromagnetic radiation is emitted and absorbed as packets of energy, called photons. It takes exactly the right energy to excite an electron to a higher energy level.

Question 29

P178

Answer 29

G