A spectrum of waves Flashcards
What is amplitude of a wave?
The amplitude of a wave is the maximum displacement of a particle from its rest position.
What is the trough of a wave?
The trough of a wave is the lowest point on a wave below its rest position.
What is the wavelength?
The wavelength of a wave is the distance between two successive points on a wave having the same displacement and moving in the same direction.
What is the crest of a wave?
The crest of the wave is the highest point on a wave above its rest position.
What is the frequency of a wave?
The frequency of a wave is the number of complete waves passing a point in one second.
Wavelength unit
Metres (m)
Frequency unit
Hertz (Hz)
Wave speed unit
metres per second (m/s)
Wave speed Eq.
wave speed = frequency × wavelength
Wavelength Eq.
wavelength = wave speed/frequency
Frequency Eq.
frequency = wave speed/wavelength
Waves in the electromagnetic spectrum from longest to shortest wavelength.
- Radio
- Microwave
- Infrared
- Visible
- Ultraviolet
- X-ray
- Gamma ray
What do some optical instruments use?
Some optical instruments such as the periscope, use two or more plane mirrors.
Why does refraction occur?
- Refraction occurs because the speed of waves decreases as the wave enters a more dense medium and increases as the wave enters a less dense medium.
- The frequency stays the same but the wavelength changes.
What is diffraction?
- Diffraction is the spreading out of a wave as it passes through a gap.
- This is why the size of a communications receiver depends on the wavelength of the radiation.
What does diffraction depend on?
- The amount of diffraction depends on the size of the gap;
- The most diffraction occurs when the gap is a similar size to the wavelength. Larger gaps show less diffraction.
- Diffraction effects are noticeable in telescopes and microscopes.
