Atoms and Radiation

Question 1

What is meant by a radioactive substance?

Answer 1

One that gives out radiation from the nucleus of its atom all the time, whatever is done to them

Question 2

Radioactive decay has a ____ nature

Answer 2

Random

Question 3

Name 2 natural sources of radiation

Answer 3

Rocks, cosmic rays from space

Question 4

Name 3 man-made sources of radiation

Answer 4

Fallout from nuclear weapons, nuclear waste, nuclear accidents

Question 5

What is an alpha particle?

Answer 5

Two neutrons and two protons, like helium

Question 6

What is a beta particle?

Answer 6

An electron from the nucleus

Question 7

What’s a gamma ray?

Answer 7

Electromagnetic radiation

Question 8

How is alpha written?

Answer 8

4
α
2

Question 9

How is beta written?

Answer 9

0
β
-1

Question 10

What is alpha stopped by?

Answer 10

5cm of air, paper, skin

Question 11

What is beta stopped by?

Answer 11

1m of air, 2mm of aluminium, thick paper

Question 12

What is gamma stopped by?

Answer 12

m’s of concrete, lead

Question 13

How ionising is alpha?

Answer 13

Highly

Question 14

How ionising is beta?

Answer 14

Medium

Question 15

How ionising is gamma?

Answer 15

Low

Question 16

Which 2 sources are deflected by an electric or magnetic field?

Answer 16

Alpha and beta

Question 17

Which source is deflected more? Why?

Answer 17

Beta, as it is lighter than alpha

Question 18

Why are alpha and beta deflected in opposite directions?

Answer 18

As they has opposite charges

Question 19

Why is gamma not deflected by a field?

Answer 19

It has no charge and is a wave

Question 20

Where is alpha used?

Answer 20

Smoke detectors

Question 21

How does a smoke detector work?

Answer 21

Alpha creates an electric current by ionising the air, when smoke particles enter the current stops- setting off the alarm?

Question 22

Why are beta and gamma used in medical tracers?

Answer 22

They have a short half life

Question 23

What are the 2 uses of beta?

Answer 23

Medical tracer, measuring paper thickness is factories

Question 24

What are the 3 uses of gamma?

Answer 24

Medical tracer, sterilising medical equipment and food, radiotherapy

Question 25

Where is alpha most harmful? Why?

Answer 25

Inside the body, as it is close to organs and cells and can ionise them

Question 26

Where are gamma and beta most harmful? Why?

Answer 26

Outside the body as they can penetrate through skin and ionise cells

Question 27

What are the 2 definitions of half-life?

Answer 27

Average time it takes for the number of nuclei in an isotope sample to halve
Time it takes for the count rate from an isotope sample to fall to half its’ initial level

Question 28

What can new evidence cause?

Answer 28

A theory to be re-evaluated

Question 29

According to the nuclear model, what is most of an atom?

Answer 29

Empty space

Question 30

What do the plums in the plum pudding model represent?

Answer 30

Electrons

Question 31

What does the pudding in the plum pudding model represent?

Answer 31

Positive charge

Question 32

What did Rutherford fire at the gold foil?

Answer 32

Fast moving alpha particles

Question 33

How thick was the gold foil?

Answer 33

A few atoms thick