# Physics

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• Created by: Najeeha
• Created on: 17-05-14 14:38

## Waves

Waves transfer energy and information without transferring matter.

Wave length: the distance between a point on one cycle and the same point on the next cycle.Measured in metres,m.

Amplitude: maximum displacement of a wave.Measured in metres,m.

Frequency: nuber of complete cycles produced or passing a point per second. Measured in Hertz,Hz.

Time period: The time taken for 1 complete cycle to be produced or pass a point.

Wave speed= frequency x wavelength

m/s                   hz        x     m

frequency=number of complete cycles                                                                                                               time taken

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## Waves

A transverse wave is one in which the direction of oscillation in the medium is perpendicular to the direction of energy transfer.

Examples: waves on a rope or spring(slinky), electromagnetic waves and waves on water

A longitudinal wave is one in which the direction of oscillation of the medium is along the direction of energy transfer.

Example: sound wave in air

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## Waves

Diffraction is the spreading out of a wave as it passes through a gap or around an obstacle.

The amount of diffraction depends upon the size of the gap and the wavelength of the wave.

The wavelength does not change if the gap is the same size as the wavelngth then diffracted wave fronts will be circular.

If the gap is much larger than the wavelength then the diffracted wavefronts are straight in the centre and get slightly longer as they travel away from the gap.

Comparing the diffraction of light and sound

We sent a student our the room and although we couldn't see her we heard her. This is because light waves don't diffract around the door as rgey have a very very small wavelength compared to sound which has a longer wavelength which diffracts around the door.

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## Waves

Light is part of a continous eletromagnetic spectrum which includes radio, microwave ,infrared,visible.ultraviolet,x-ray and gamma ray radiation, all these waves travel at the same speed in free space

Increasing frequency

microwaves Musicians

Infrared Improvise

Visible light Very

Ultraviolet Unusual

X-rays Xylophone

gamma rays grooves

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