physics P1 (4)

Waves

• waves transfer energy from a source to other places
• waves are a regular pattern of disturbances
• in a transverse wave the disturbance is a right angles to the direction of travel of the wave
• in a longitudinal wave the disturbance is parallel to the direction of travel of the wave
• the amplitude is the maximum disturbance from equilibrium
• it is measured in metres
• the wavelength is the distance between one point on a disturbance and the same point on the next one eg, from crest to crest, tough to tough
• it is measured in tough
• the prequency is the number of waves produced by the source in one second, or the number od waves passing a point in one second
• it is measured in hertz

Diffraction

• all waves can be reflected
• all waves can be refracted
• all waves can be diffracted
• diffraction is the bending of a wave into the region of shadow as it passes an obstacle
• -the wavelength, frequency and speed of the wave do not change
• -the longer the wavelength, the more the wave is diffracted
• when drawing diagrams to show diffraction, we use waveforms, not rays
• since light has a very small wavelength these is only a very small amount of diffraction
• sonce sound has a longer wavelength these is a larger amount of diffraction so sound is bent round corners

Waves through gaps

• gap large compared to wavelength and there is little diffraction
• gap smaller and a little more diffraction
• gap the same size and wavelength and the waves become curved

Waves past obstacles

• obstacle large compared to wavelength and there is little diffraction
• obstacle smaller and there is more diffraction
• obstacle the same size as the wavelength and the waves meet as they cross over

Reflection

• the image produced in the mirror is virtual, it is formed where the rays appear to come from
• it is also upright ans laterally inverted…