Light waves Flashcards
What is a wave?
Waves are one of the ways in which energy may be transferred between energy stores.
How could you describe a wave?
Waves can be described as oscillations, or vibrations about a rest position.
What are mechanical waves?
Mechanical waves: are waves that require a medium e.g. air/water. This means that they have to have some sort of matter to travel through.
What are electromagnetic waves?
Electromagnetic waves: are waves that can travel through a vacuum (empty space). They don’t need a medium or matter.
Give an example of a longitudinal wave.
Sound waves are longitudinal waves.
Give an example of a transverse wave.
Light waves are transverse waves.
What is the direction of travel of the vibrations in a longitudinal wave?
In longitudinal waves, the vibrations are parallel to the direction of wave travel.
What is the direction of travel of the vibrations in a transverse wave?
In transverse waves, the vibrations are at right angles to the direction of wave travel.
What is the peak of a wave?
Peak - the highest point of a wave (above the rest position).
What is the trough of a wave?
Trough - the lowest point of a wave (below the rest position).
What is meant by the ‘amplitude’ of a wave?
Amplitude - the distance from the middle of a wave to the top (peak) or bottom (trough) of a wave. The ‘loudness’ of a sound.
What is a wavelength?
Wavelength - the distance from one point on a wave to the same point on another wave. Usually measured from peak to peak, or trough to trough
What is frequency of a wave?
Frequency - the number of waves passing a particular point each second. Frequency is measured in hertz (Hz). The pitch of a note depends on it’s frequency.
What is the difference between transparent and translucent materials?
A transparent material lets almost all the light pass through whereas a translucent material only allows some of the light through.
Can light travel through an opaque material?
No, an opaque material does not allow light to pass through. e.g. wooden table, mirror
What is a luminous object?
Luminous objects are objects that give out their own light e.g. the sun, candle flame.
Define specular reflection
Reflection from a smooth, flat surface is called specular reflection. This is the type of reflection that happens with a flat mirror.
Define diffuse scattering in terms of reflection
If a surface is rough, diffuse reflection happens. Instead of forming an image, the reflected light is scattered in all directions.
What does the law of reflection state?
‘’when light is reflected from a smooth surface e.g. a mirror, the angle of incidence is equal to the angle of reflection.’’
What is meant by the term ‘refraction’ of light.
Refraction of light is the BENDING of light when it passes from one medium (e.g. air) to another medium (e.g. water).
The image shows a transverse wave. What is label W the image?
Peak/crest
The image shows a transverse wave. What is label Y the image?
Trough
The image shows a transverse wave. What is label Z the image?
Wavelength
The image shows a transverse wave. What is label X the image?
Amplitude
What are the 7 colours of white light?
Red, orange, yellow, green, blue, idigo and violet
When white light passes through a _____________ it splits into it’s 7 different colours.
Prism
The splitting of white light when it passes through a prism is called _____________.
Dispersion
