GCSE Science | Waves
What is a wave?
Waves are a transfer of energy.
What is a transverse wave?
In transverse waves, the vibrations are perpendicular to the direction of the wave e.g. electromagnetic waves, water waves
What is a longitudinal wave?
In longitudinal waves, the vibrations are parallel to the direction of the wave e.g.sound waves | | | ||| ||| | | ||
What do all electromagnetic waves have in common?
Electromagnetic waves are always transverse, travel at the same velocity through a vacuum.
What is the electromagnetic spectrum?
HIGHEST WAVELENGTH, LOWEST FREQUENCY
- RADIO: tv and radio
- MICROWAVES: satellite communications, cooking food
- INFRARED: electrical heaters, cooking food, infrared cameras
- VISIBLE LIGHT: fibre optic communications
- ULTRAVIOLET: energy efficient lamps, sun tanning,
- X-RAYS and GAMMA: medical imaging and treatments.
LOWEST WAVELENGTH, HIGHEST FREQUENCY
What is amplitude?
Amplitude is the maximum displacement of a point on a wave away from its undisturbed position (high amplitude = high volume).
What is wavelength?
Wavelength is the distance between two consecutive peaks on a wave.
What is the frequency of a wave?
Frequency is the number of waves passing a point per second (high frequency = high pitch).
What is the time period of a wave?
The time Period of a wave is the time taken for each wave to pass a point.
T = 1/f
T: time period (s)
f: frequency (Hz)
v = fλ
f: frequency (Hz)
v: speed (m/s)
λ: wavelength (m)
How are radio waves produced?
Radio waves are produced by oscillations in circuits.
The radio waves have the same frequency as these oscillations.
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)
If the medium is more dense
The wave will slow down and move towards the normal
If the medium is less dense
The wave will speed up and move away from the normal
Summary questions
- what is a wave?
- what is a transverse wave?
- what is a longitudinal wave?
- label wavelength and amplitude on a wave
- what do all electromagnetic waves have in common?
- electromagnetic spectrum
- what are the units in v = fλ
- what are the units in f = 1/T
- how are radio waves produced?
- refraction