Frequency= number of waves that pass a point per second
Waves transfer energy
The EM Spectrum
Transverse waves
Travel through vacuum at speed of light
High frequency=more energy transferred
Law of Reflection
Images in mirrors
Virtual
Upright
Laterally inverted
Angle of reflection= Angle of incidence
Period of a Wave
Period= Time (T)
Frequency= F
F= 1/T
T=1/F
Period= 1/ Frequency
Frequency= 1/Period
Refraction
Refractive Index
In the equation above, v1 is the speed of light
in a vacuum. The bigger the refractive index
the slower the light travels in that material -
i.e. the smaller v2 is.
Refraction is the bending of a wave when it enters a medium where its speed is different. The
refraction of light when it passes from a fast medium to a slow medium bends the light ray toward
the normal to the boundary between the two media. The amount of bending depends on the index
of refraction of the two media and is described quantitatively by Snell's Law.
Snell's Law
Total Internal Reflection
Dispersion
Light waves can be dispersed by a prism which
separates white light into a rainbow because each
colour has a different refractive index
Angle of incidence must be greater than the critical angle
Used in fibre optics
Swap Sin C and n to work it out the other way round...
Sound Waves
Reflection of sound
Sonar
Bats use sonar to communicate (ultrasound squeaks)