Waves revision cards Flashcards
Describe the oscillations in a transverse wave.
The oscillations are PERPENDICULAR to the direction of wave travel
Describe the oscillations in a longitudinal wave.
The oscillations are PARALLEL to the direction of wave travel.
Define wave frequency and give the unit.
Number of oscillations per second, measured in Hertz (Hz).
What is the period of a wave?
The length of time it takes one complete wave to pass a given point, in seconds.
What is the wavelength of a wave?
The distance, in metres, from a point on one wave to the same point on the next wave e.g. peak to peak (symbol: λ)
What is the amplitude of a wave?
The maximum distance from rest position, measured in m.
What is the equation linking wave speed, frequency and wavelength?
v = f x λ
where
v = velocity (m/s)
f = frequency (Hz)
λ = wavelength (m)
What is it called when a wave changes direction at a boundary between two media?
Refraction
Light speeds up as it exits a glass block, which way does it refract? (Towards/Away from the normal)
Away from the normal.
Speed Away!
When a wave refracts, which two of the following change? v, f, λ?
v & λ
a change in speed (v) causes refraction. This change in speed can cause wave fronts to bunch up/spread out causing a change in wavelength (λ)
Visible light, microwaves and X rays are all types of what?
Electromagnetic wave
William Herschel discovered infrared by placing what just outside of a visible spectrum?
Thermometers
List the regions of the EM spectrum in order, from longest wavelength to shortest.
Radiowaves
Microwaves
Infrared
Visible light
Ultraviolet
X rays
Gamma ray
(Remember my instructions, visible under x ray glasses)
The atmosphere absorbs most types of EM waves, but there is one type of telescope that works well from the surface of the Earth as the waves are not absorbed. Which type of telescope is this?
Radio telescopes (giant white dishes!)
How are radio waves produced?
Oscillations in electrical circuits.
