P11 Flashcards
How to tell if it is a transverse wave
The oscillations (vibrations) are perpendicular to the direction of energy transfer. The vibrations go up and down
How to tell if it is a longitudinal wave
The oscillations are parrellel to the direction of energy transfer. Straight line, some parts compressions and some rarefractions
What is the amplitude of a wave
Maximum displacement of a point on the wave from its undisturbed position
What is the wavelength
Distance between same point on 2 adjacent waves
What is the frequency
Number of complete waves passing a certain point per second
Example of transverse waves
Light, radio, microwaves, infared, radation, visible light, ultraviolet, x rays, gamma rays
(EM SPECTRUM)
Example of longitudinal wave
Sound, ultrasound, infrasound, earth quakes
What 3 things happen when a wave meets a boundary between 2 materials
- the wave is absorbed by the second material
- the wave is transmitted through the second material
- the wave is reflected
What is refraction
Waves changing direction at a boundary
How do we know if a wave has been refracted
If the wave hits the boundary at an angle and it changes directik
How do we know how much it is refracted
Depends on how much the wave speeds up or slows down
What does the speed of the wave depend on
The density of the material - the higher the density of the material, the slower the wave travels through it
What is the optical density of a material
Optical denisty of a material measures how quickly light can travel through it
What stays the same and what changes when a wave is refractsd
The frequency stays the same byt the wavelength changes
Amplitude
Height of a wave crest or trough wave from the rest position
Electromagnetic waves
Electric and magnetic dusturbances that transfer enrrgy from 1 place to another
Oscillate
Move to and fro about a certain position along a line (transverse waves)
Reflection
Change of direction of a wave at a boundary when the wave stays in the incident medium
Go to page 219 for the practical
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What are the two uses of waves?
Energy and information
What do mechanical waves need?
A medium to travel through
How to demonstrate a longitudinal wave?
Slinky to demonstrate sound waves
Period of a wave:
1/frequency
Reflection test
Plane waves in a ripple tank are reflected from a straight barrier at the same angle to the barrier as the incident waves becuase their speed and wavelength dont change the reflection
Plane waves crossing a boundry:
They are refracted unless they cross the boundary at a normal incidence
