Waves pt1 Flashcards
Transverse
The wave is perpendicular to the force applied
Waves up and down e.g. a spring
Longitudinal
Oscillations parallel to energy transfer
Compresses and extends e.g. ultrasound in air
Drawings
Transverse goes up and down, longitudinal have flat lines
Period
1/ frequency
Amplitude
Maximum displacement of a point on the wave from its undisturbed position
Wave speed=
Frequency x wavelength
What can all waves be?
Be Absorbed, reflected and transmitted
Reflecting
Angle of incidence = angle of reflection
Normal
A perpendicular line to the surface at the point of incidence (dotted line)
Speculation reflection
When a wave is reflected in a single direction by a smooth surface to make a clear line of reflection
Diffuse reflection
When a wave is reflected by a rough surface to scatter the reflected rays in a lot of direction (surface appears matte and there won’t be a clear reflection)
Refraction
When a wave crosses a boundary between materials and changes direction
The density affects the extremity of this
Quicker waves through less dense objects are refracted away from the normal
What are radio waves made of (1/2)
Oscillating charges and magnetic fields
AC are made up of oscillating charges to produce these
Frequency of ac = wave frequency
Can produce radio waves with a transmitter in an ac circuit
What are radio waves made of (2/2)
Absorbed by a receiver
Energy from waves is transferred to electrons
Electrons oscillate to generate an ac in a circuit
Has the same frequency as the waves that generated it
Radio waves
EM radiation with wavelengths over about 10cm
Lamb radio waves have wavelengths of 1-10km can diffract around curves
Short waves (10-100m) are reflected from the ionosphere and medium waves depending on time of day
