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Flashcards in Unit 1 Deck (47):
1

Which wave oscillates at 90* to the motion of travel?

Transverse waves

2

Which wave oscillates at 180* to the motion of travel?

Longitudinal wave

3

Define the frequency of a wave

The number of waves that pass per unit of time

4

What is diffraction?

The bending of waves around an object or through an opening

5

Will a shorter wavelength diffract more or less than a longer wavelength?

Less

6

Will a wavelength diffract more through a wider opening compared to a narrower opening?

No it will diffract more through a narrower opening

7

Name the electromagnetic spectrum from longest wavelength to shortest

Radio waves, microwaves, infrared, visible light, UV, X-rays, gamma rays

8

Do all waves in the electromagnetic spectrum travel at the same speed?

Yes they all travel at the speed of light, 3 x 10^8

9

What do all the electromagnetic groups have that is different?

Wavelengths

10

Give a use of radio waves

Communication

11

Give a use of microwaves

Cooking food

12

Give a use of infrared

Remotes

13

Give a use of visible light

To see

14

Give a use of UV

Killing microbes

15

Give a use of X-rays

To see your bones inside your body

16

Give a use of gamma rays

Killing cancer cells

17

What type of wavelength has the highest amount of energy?

Shorter waves
EG - gamma rays

18

What is refraction?

The changing of speed as light passes from one material to another

19

All angles should be measured from where?

The normal, an imaginary line at 90* to the surface

20

What is the name of the light striking the surface?

Incident ray

21

What is the name of the ray of light passing through the material?

Refracted ray

22

What is meant by the term 'critical angle'?

It is the angle at which total internal reflection occurs, if the angle is increased further

23

What does total internal reflection mean?

Light is reflected off of the inside of the material at the same angle it was incident at

24

What are the three main types of nuclear radiation?

Alpha, beta and gamma

25

What is the minimum blockage of alpha?

A sheet of paper

26

What is the minimum blockage of beta?

A few mm of aluminium

27

What is the minimum blockage of gamma?

A few cm of lead

28

Which type of radiation is the most ionising?

Alpha

29

What is meant by the term 'ionisation'

It is the gain or loss of electrons from atoms, turning them into charged ions

30

Where does background radiation come from?

Cosmic rays, human body, radioactive gas, rocks, soil and buildings

31

What is activity?

The number of decays per unit time

32

What is activity measured in?

Bequerels, 10Bq means that 10 decays have occurred per second

33

What is absorbed dose?

The energy absorbed per unit of mass

34

All waves transfer what from one place to another?

Energy

35

What is absorbed dose measured in?

Greys, 80 mGy means that 80 mJ have been absorbed per kilogram

36

What is equivalent dose rate a measure of?

The biological effect or damage a type of radiation may cause

37

What is equivalent dose measured in?

Sieverts, H = Dwr

38

What does the overall risk from exposure depend on?

The equivalent dose, type of radiation, type of tissue involved

39

What is 'half-life'?

The time taken for the activity to reduce by half

40

How could you measure the half life of a radio active material?

Background counts must be found first. This is taken away from the counts with the source present. A graph of corrected count against time is plotted

41

What happens in nuclear fission?

A large nucleus will split into small nuclei. This releases energy and possible more neutrons. Can be spontaneous or induced by using a neutron bombardment

42

What happens in a nuclear power station?

Nuclear fission is used. Energy held by Uranium is realised during fission to produce heat. Heat absorbed by CO2 gas. The heat is passed onto water to turn into steam which turns a steam turbine. Spinning motion produces electrical energy

43

What happens in nuclear fusion?

Small nuclei will join together to form a larger nucleus. This will release energy

44

What can radioactivity be used for?

To sterilise medical equipment

45

Why must gamma radiation be used to treat cancer?

It is the only type of radiation that can pass through the human body

46

What can used to find blockages inside the human body?

A medical tracer that emits gamma rays

47

What can be used to detect the amount of radiation received by a person?

A film badge