Waves Flashcards
What are waves?
Waves are oscillations (or vibrations) that cause the transfer of energy.
Do oscillations occur around one fixed point?
Yes, oscillations occur around a fixed point, while the wave energy moves in a particular direction.
What are the two types of waves?
- Mechanical Waves
- Electromagnetic Waves
Which type of wave requires a medium?
Mechanical waves require a medium (solid, liquid, gas), however electromagnetic waves do not require a medium.
Which type of wave can travel through a vacuum?
Electromagnetic waves can travel through a vacuum, solid, liquid and gas, but mechanical waves cannot travel through a vacuum.
What are examples of mechanical waves?
Sound waves, seismic waves, water waves, moving objects (Rope and slinky)
What are examples of electromagnetic waves?
Radio waves, micro waves, light waves, visible light, ultraviolet radiation, x-ray, gamma waves
What do mechanical waves require?
Mechanical waves require a disturbance of the medium which causes particles to vibrate.
What do electromagnetic waves require?
Electromagnetic waves require a source that generates electromagnetic oscillations.
What is wave motion?
Waves can involve different types of oscillations (vibrations); there are two main types of wave motion.
What are the two main types of wave motion?
Transverse Waves and Longitudinal Waves
What are transverse waves?
Transverse waves are oscillations perpendicular to the direction of the wave.
What are examples of transverse waves?
All electromagnetic waves and waves caused by a rope moving up and down.
What are longitudinal waves?
Longitudinal waves are oscillations travelling in the same direction to the direction of the wave.
What is an example of a longitudinal wave?
Sound waves
What are surface waves?
In surface waves, oscillations are circular. These can be considered as a hybrid between transverse and longitudinal waves.
Where do surface waves occur?
Surface waves occur at the interface of two different media.
What are examples of surface waves?
Waves in water (although these are often incorrectly described as transverse waves) and seismic surface waves.
What are the different parts of a wave?
Amplitude, wavelength, trough, crest and resting position.
What is amplitude?
Amplitude is the distance between the original starting position and the maximum point of oscillation.
What is wavelength?
Wavelength is the distance from a crest/trough of a wave to the crest/trough of the next wave.
What is the unit for wavelength?
metres (m)
What is frequency?
Frequency is the number of waves passing a point every second.
What is the unit for frequency?
Hertz (Hz)
What is velocity?
Velocity is how fast a wave transmits energy through space.
What is resting position?
Resting position is the position where the wave settles down when there is no power being carried through it.
What is the crest?
The crest is the highest point of oscillation.
What is the trough?
The trough is the lowest point of oscillation.
Are frequency and wavelength inversely proportional?
Yes, frequency and wavelength are inversely proportional, which means that the higher the frequency, the shorter the wavelength.
What does EMS stand for?
Electromagnetic spectrum
What are some examples of EMS?
Micro waves, sound waves, x-ray, radio waves, ultraviolet waves and gamma waves.
How are EM waves similar to ocean waves?
They both transmit energy, and they both have a crest and a trough.
How are EM waves produced?
Oscillation (vibration) of charged particles.
What properties do EM waves have?
Electromagnetic waves involve vibrations of electric and magnetic fields; an electric field and a magnetic field oscillating together.
At what speed do EM waves travel through space?
EM waves travel at the constant speed of light through space.
How long can a wavelength be?
The length of wave can be very long but many are very short.
What is the difference between long EM waves and short EM waves?
Long EM waves have the lowest frequency and carry less energy, whereas gamma waves are the shortest and have the highest energy in the spectrum.
What is the effect of adding energy on the frequency of a wave?
Adding energy increases the frequency of a wave and makes the wavelength shorter.
What is the visible light spectrum?
The section of the electromagnetic spectrum that is the visible light (the human eye can see). This is between 400 and 700 nanometres.
What happens to visible light waves when they interact with objects?
EM waves interact with the object’s molecules, creating colour. Some waves reflect off the object, but others are absorbed.
What is a spectral signature?
Everything around us emits, reflects and absorbs EM radiation differently based on its composition. A graph showing these interactions across a region of the EM spectrum is called a spectral signature.
What is the lowest energy end of the EM spectrum?
At the lowest energy end of the spectrum are radio waves, which have the longest wavelength and the lowest frequency.
What is the highest energy end of the EM spectrum?
At the highest energy end of the spectrum are gamma rays, which have the shortest wavelength and the highest frequency.
Does the higher the energy of the electromagnetic radiation, mean the greater penetration of matter?
Yes, the higher the energy of the electromagnetic radiation, the greater the penetration of matter (ability to penetrate objects).
