# Physics Unit 1 waves

It includes transverse and longitudinal waves, the electromagnetic spectrum, diffraction, refraction and reflection.

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• Created by: Francesca
• Created on: 02-06-12 10:51

First 105 words of the document:

Waves
Amplitude ­ The displacement from rest position
to crest. Measured in m or cm
Wavelength ­ the length of a full cycle of the wave
i.e. crest to crest. Measured in nm / m
Frequency ­ number of complete waves passing a
certain point per second. Measured in Hertz (Hz).
Time Period ­ The time it takes to make one
oscillation.
- The relationship between Time period and
frequency is f=1/T
Transverse waves
In Transverse waves the vibrations are at a 90
degree angle to the direction of travel of the
wave.

## Other pages in this set

### Page 2

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Examples = electromagnetic waves, ripples on
Longitudinal waves
In Longitudinal waves the vibrations are along the
same direction as he wave travelling.
Examples are sound waves, ultrasound and Shock
waves.
The wave equation
Velocity = Frequency x wavelength
E.g. it F=2 and W=4 then V=8
Display of sound waves
The greater the amplitude the louder the sound
The longer the period of vibrations, then the lower
the frequency and the lower the pitch.…read more

### Page 3

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Electromagnetic waves
There are 7 types of electromagnetic waves
wavelength.
Microwaves
Infra Red
Visible light
Ultra violet
X-Rays
Gamma rays ­ Highest frequency, lowest
wavelength
All EM waves travel at the same speed through
a vacuum.
Waves with shorter wavelengths have a higher
frequency.
Waves at each end of the EM spectrum can pass
through a material where as waves nearer the
middle get absorbed.
When EM radiation is absorbed it can cause

### Page 4

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Diffraction is when waves bend round an obstacle
How it works
- All waves spread out at the edges when they
pass through a gap or past an object.
- The amount of diffraction depends on the size of
the gap relative to the wavelength of the wave.
The narrower the gap, or the longer the
wavelength the more the wave spreads out.
Refraction
Waves travel at different speeds in substances,

### Page 5

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When the wave reaches the air to another
media boundary it speeds up and bends away
from the normal.
Reflection
When waves rebound of the material and reflect
of it at the same angle.…read more