# physics unit 1- waves

HideShow resource information
• we use waves to transfer energy and information
• two types of wave : 1) tranverse- the oscillation of particles is up and down (at right angles to the direction at which it travels)  2) longitudinal- the oscillation of particles is across (parallel to direction at which it travels)
• longitudinal waves have compressions and rarefractions
• electromagnetic waves= light and radio waves can travel through a vacuum as there are no particles in the wave- ALL ARE TRANSVERSE
• mechanical waves= waves on springs and sound waves can travel through a medium- CAN BE LONGITUDINAL OR TRANSVERSE
• sound waves are longitudinal
• ampltiude- the height of the wave crest from rest position
• the wavelength- distance of one wave crest to the next
• frequency- number of crests passing one point in a second
• speed of wave= frequency (hz)  x wavelength (m)
• frequncy of a longitudinal wave is amount of compressions passing one point in a second
• image seen in a mirror is due to reflection of light
• angle of insidence- angle between ray i and the normal
• angle of refraction- angle between ray r and the normal
• for any relflected ray ANGLE OF INSIDENCE= ANGLE OF REFRACTION
• imagine in a plane mirror= upright, virtual, same distance behind mirror as infront
• REAL IMAGE- can be formed on a screen…