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WAVES
- transports energy as it progresses from one point to another, without moving matter
- travel through the medium and carry energy but do not take the medium with them
- cause an oscillation of the particles in the medium but each particle of the medium returns to the equilibrium position (stable systems). ...
Mechanical waves
- require a physical elastic material medium to travel (sound waves, water waves earthquake waves)
- produced by disturbing or vibrating a material medium
Non mechanical waves
- do not require medium to travel and travel through empty space and vacuum (electromagnetic and gravitational waves)
- created by vibrating fields or disturbing a field
- a change in field progresses outward causing the energy to move as well
1. Transverse waves are waves in which the particles of the medium vibrate at 90 degrees (perpendicular) to the waveˇ¦s velocity. (electromagnetic waves, water waves, stretched strings)
2. Longitudinal/Compression waves- the medium move back and forth parallel to the waveˇ¦s velocity (Sound waves, P waves of earthquakes). ...
The speed of these waves depends on the medium through which it travels. ... (a large inertia will give a slow velocity)
Wavelength ( )- is the distance between 2 consecutive identical points ( 2 crests or 2 troughs)
Amplitude (A)- transverse waves- maximum displacement of the medium from its equilibrium position
- compression waves- maximum displacement from equilibrium of any of the particles. ...
I A
- if the waves spread out spherically from a point, their intensity will decrease in proportion to the inverse square from the distance. (applies to electromagnetic waves)
I 1
- intensity decrease as the same amount is used to spread over a larger distance. ... at 1m- intensity = 4lux
2m- intensity = 1/4 of the original = 1/4 x 4 = 1 lux
3m- intensity = 1/9 of the original = 1/9 x 4 = 4/9 lux
Superposition
- when pulses or wave actively meet called interference
- At any point where 2 waves overlap, the total disturbance is the sum of the individuals disturbance caused by each wave at that point
- amplitudes are added together
- waves can pass through one another and emerge unchanged
- applications: superposition of reflected sound waves in car mufflers to reduce exhaust noise or reduce the sound emitted by heavy machinery in factories.
Approximate Word count = 1550 Approximate Pages = 6.2 (250 words per page double spaced)
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