Flashcards in 1. Waves Deck (28)
What do all waves transfer?
What is frequency (f)?
Frequency is the number of waves produced per second
What is the frequency equation?
f =N/t (number of waves over time)
What is a wavelength (λ)?
The distance from one point of a wave to the same point on the next wave
What is the amplitude of a wave?
The distance from a waves mid point, to its crest or trough
What is a period (T)?
A period is the time between each wave (related to frequency)
The time it takes for a wavelength to pass a point
What is the period equation?
T = 1/f (number one over frequency
What is a transverse wave? Give examples
A wave which travels at a right angles to the direction of its origin (up and down)
E.g. X-ray, water
What is a longitudinal wave? Give examples
A wave which travels in the direction of its origin (side to side)
What is the equation which can be used to determine the time it takes for a wave to travel a certain distance?
v = fλ (frequency times wavelength)
v = d/t (speed, distance, time equation)
What is the range of human hearing?
20 Hertz (Hz) to 20 000 Hertz
What are sounds above the range of human hearing called?
What happens when waves hit a barrier?
When waves hit a barrier they diffract, spreading out around the back of the barrier
Higher frequencies diffract better than lower frequencies
True of False?
False - they diffract less well than lower frequencies
What speed do electromagnetic spectrum waves travel at?
What is the order of the electromagnetic spectrum, from shortest to longest?
Gamma rays, X-rays, Ultraviolet rays, Visible light, Infra-red, Microwaves, TV/Radio waves
(Good Xylophones Usually Vibrate Intensely Meanwhile Tambourines Rattle)
If Gamma rays have a high frequency then is their wavelength likely to be short or long?
Short, and they carry the most energy
When light waves move from one material to another, what change will it undergo? And what will the ray bend towards?
A change in direction
It will bend towards the normal
Expansion - This means that when light moves to a more optically dense material, the speed of light slows, and the wavelength shortens
What are the light rays going into, and leaving a glass block called?
And what are the angles between these rays and the glass block called?
The incident ray (going in) and the refracted ray (coming out)
Angle of incidence and the angle of refraction
Which type of light enters a glass prism, and what type of light is it refracted into?
When monochromatic light (white light) refracts in a glass prism, it splits up, revealing the colours of the visible portion of the electromagnetic spectrum (the rainbow)
What is a critical angle?
The point at which the ray of light stops refracting, and total internal reflection occurs
What occurs when the angle of refraction is so large the refracted ray does not leave the material?
Total Internal reflection
Total internal reflection is a useful property of light, why is this?
It can be used to allow light to travel down a fibre optic cable
What does a convex lens look like, and what does it do to light? Give examples
Convex lenses look like this: ()
They converge light to a single point called the focal point
What does a concave lens look like, and what does it do to light? Give examples
Concave lenses look like this: )(
They spread light out, meaning the focal point is actually being the lens
E.g. "spy holes" in doors
The focal length is measured between the lens and the focal point
True or False?
Which lens would a person with long sightedness use?
This means the person cannot focus things near to them, so we want to bring the focal point forward
Therefore we would use a convex lens