Waves

The difference between longitudinal and transverse wave:

Transverse                                                           Longlitudinal

-travel away from the source                               -waves parallel to the direction of travel

-waves are perpendicular the the direction         -don't travel through a vaccum

-electromagnetic wave                                        -need particles to travel

-travel though a vaccum at the speed of light     -rare to have, usually found in sound & light waves

-don't need particles to travel

Amplitude-maximum displacement from the equilibrium point

Wavefront-is a surface over which an optical wave has a constant phase. For example, when a stone is dropped in still water, waves spread out along the surface of the water in all directions with the same velocity. Every particle on the surface vibrates. Wavefront, imaginary surface representing corresponding points of a wave that vibrate in unison

Frequency-is the number of times a point on a wave passes a fixed reference point in one second. The period or duration of time of a cycle of a wave is the reciprocal (1 divided by) of frequency. The SI unit for frequency is the Hertz (Hz), which is equivalent to the older unit cycles per second (cps).

Wavelength- distance between two corresponding points on a wave

Period of a wave- is the time it takes to complete one cycle

wave speed = frequency × wavelength 

v = f × λ

frequency = 1/time period

f = 1/T

 why there is a change in the observed frequency and wavelength of a wave when its source is moving relative to an observer, and that this is known as the Doppler effect

When an object moves towards an observer, the wavelength shrinks, so the frequency increases. In terms of sound waves, this means that the pitch increase.
When an object moves away from the observer, the wavelength increases, so the frequency decreases. In terms of sound waves, this means that the pitch decreases.
The Doppler Effect is the apparent change in frequency of a wave caused by the relative motion between the source of the wave and an observer.

explain that all waves can be reflected and…