Unit 1: 5 - Waves Flashcards
In what direction is the oscillation of a transverse wave?
Perpendicular to the direction in which the wave travels.
In what direction is the oscillation of a longitudinal wave?
Parallel to the direction in which the wave travels.
What is a longitudinal wave made up of?
Compressions and rarefactions.
What type of waves can travel through a vacuum?
Electromagnetic waves.
What type of waves must travel through a medium?
Mechanical waves.
How do we find the amplitude of a transverse wave?
The distance from the height of the wave crest/depth of the wave trough to the rest position.
How do we find the wavelength of a transverse wave?
The distance to one crest/trough to the next crest/trough respectively.
How do we find the frequency of a transverse wave?
The number of wave crests/troughs passing a point in 1 second, measured in Hz.
How do we work out the speed of a wave?
v (m/s) = f (Hz) * λ (m)
Speed = frequency * wavelength
How do we find the wavelength of a longitudinal wave?
It is the distance from the middle of 1 compression to the middle of the next (same applies to rarefactions).
How do we find the frequency of a longitudinal wave?
The number of compressions passing a point in 1 second.
What is the angle of incidence?
The angle between the incident ray and the normal.
What is the angle of reflection?
The angle between the reflected ray and the normal.
In a reflected ray (not refracted), what is the relationship between the angle of incidence and the angle of refraction?
They are equal.
The image in a plane mirror is… (give 4)
- The same size as the object;
- Upright;
- The same distance behind the mirror as the object is in front;
- Virtual.
What is a real image?
An image that can be projected onto a screen, because the rays of light that produce the image actually pass through it.
What is a virtual image?
An image that cannot be projected onto a screen, because the rays of light that produce the image only appear to pass through it.
When do waves change speed and refract?
When they pass through a boundary between different substances.
What type of waves is refraction a property of?
All waves.
How does the change in speed of waves affect the wave?
It changes direction.
When entering a more dense substance, the ray _____ and the ray changes direction _____ the normal.
Slows down, towards.
When entering a less dense substance, the ray _____ and the ray changes direction _____ the normal.
Speeds up, away.
Why does white light split when directed into a triangular prism, and what is this called?
As white light contains different colours of light with different wavelenghts, they refract at a different rate, producing a spectrum. This is called dispersion.
What colour of visible light is refracted the most?
Violet
