The trough of a wave is the lowest point
on a wave below its rest position.
The crest of a wave is the
highest point on a wave above
its rest position.
The wavelength of a wave is
the distance between two
successive points on a wave
having the same displacement
and moving in the same
direction
The frequency of a wave is the number of complete
waves passing a point in one second.
The equation for the speed of a wave is: wave speed =
frequency × wavelength
Electromagnetic Spectrum
Radio
Microwave
Infared
Visable
Ultra Violet
X- ray
Gamma
Getting the message across
Some optical instruments, such as the
periscope, uses two or more plane mirrors.
Refraction occurs because the speed of waves
decreases as the wave enters a more dense
medium and increases as the wave enters a less
dense medium. The frequency stays the same
but the wavelength changes.
Diffraction is the spreading
out of a wave as it passes
through a gap.
The size of a communications
receiver depends on the
wavelength of the radiation.
Diffraction Effects
The amount of diffraction depends on the
size of the gap; the most diffraction occurs
when the gap is a similar size to the
wavelength. Larger gaps show less
diffraction.
Diffraction effects are noticeable in
telescopes and microscopes