Waves Flashcards
(27 cards)
What is a wave?
A wave transfers energy without any overall transfer of matter.
How is a wave created?
To create a wave something needs to vibrate, the thing that vibrates is called a medium and it can be a collection of particles or electromagnetic field.
What evidence is there that a wave doesn’t transfer matter?
In a water wave the water particles don’t all travel towards land otherwise there would be a displacement of water.
What is a transverse wave?
A transverse wave is that travels perpendicular (at right angles) to the direction of energy transfer.
Give 3 examples of transverse waves.
Electromagnetic waves (e.g light) ,water waves and s-waves.
What is a longitudinal wave?
A longitudinal wave is a wave the travels parallel to the direction of energy transfer.
What is a rarefaction and a compression in a longitudinal wave?
In a longitudinal wave a rarefaction is when the particles are further apart and a compression is when the particles are closer together.
Give 3 examples of longitudinal waves.
Sound waves, ultrasound waves and P-waves.
What is the frequency of a wave?
Frequency is the amount of waves per second. It is measured in Hz (Hertz)
What is the time period of a wave?
The time period is the amount of time for one wave to occur.
What is the amplitude of a wave?
The amplitude of a wave is the maximum displacement of a wave from it’s resting point.
What is the wavelength of a wave?
The wavelength of a wave
What is wave speed?
Wave speed is the rate at which energy is transferred through the medium.
What is the difference between diffuse and specular reflection?
Specular reflection is when light reflects off a smooth surface and waves remain parallel after reflection. On the other hand, diffuse reflection is when light reflects off a rough surface and waves scatter in different directions.
How do you draw a ray diagram to show images in mirrors?
Can’t show images.
What is a virtual image?
A virtual image is one from which the light rays appear to come from but don’t actually come from.
What is a real image?
A real image is an image where the light rays do come from.
What is refraction?
Refraction is when a light ray enters a substance with a different optical density and this causes the light ray to change speed which then causes a change in direction.
What happens to a waves frequency and wavelength in refraction?
When a wave undergoes refraction the frequency stays the same but the wavelength changes. If a wave speeds up the wavelength will increase and if the speed decreases then the wavelength will also decrease.
What does the refraction of light cause?
The refraction of light at water/ air boundaries causes the object to appear closer than it is.
What happens to parallel rays of light when they enter a convex lens?
When parallel rays of light enter a convex lens they will converge to a point known as the focal point and the focal length is the distance between the centre of the lens and the focal point.
How do objects viewed through a convex lens appear?
What happens to parallel rays of light when they enter a concave lens?
When parallel rays of light enter a concave lens they diverge away from the focal point. For concave lens the focal point is on the same side as the object.
How do objects viewed through a concave lens appear?
