Transverse waves: the vibrations are perpendicular to the direction of the wave (water, EM waves)
What is a longitudinal wave?
Longitudinal waves: the vibrations are parallel to the direction of the wave (sound) e.g. | | | ||| ||| | | ||
What is the electromagnetic spectrum?
HIGHEST WAVELENGTH, LOWEST FREQUENCY
Uses: RADIO: tv and radio, MICROWAVES: satellite communications, cooking food, INFRARED: electrical heaters, cooking food, infrared cameras, VISIBLELIGHT: fibre optic communications, ULTRAVIOLET: energy efficient lamps, sun tanning, X-RAYS and GAMMA: medical imaging and treatments.
LOWEST WAVELENGTH, HIGHEST FREQUENCY
What do all electromagnetic waves have in common?
Electromagnetic waves are always transverse, travel at the same velocity through a vacuum.
What is amplitude?
Amplitude: the maximum displacement of a point on a wave away from its undisturbed position (high amplitude = high volume).
What is the frequency of a wave?
Frequency: the number of waves passing a point each second (high frequency = high pitch).
What is the time period of a wave?
Period: the time taken for one wave to pass a point.
Wave equations
T = 1/f
v = fλ
T: time period (s), f: frequency (Hz), v: speed (m/s), λ: wavelength (m)
Radio waves
radio waves can be produced by, or can themselves induce, oscillations in electrical circuits
What is refraction?
waves can refract, reflect, be transmitted, and be absorbed.
Refraction is when waves change direction as they enter a new medium (air/glass/water)