P6 - Waves Flashcards
What are the 2 types of wave?
Transverse and longitudinal waves
What is the difference between a
transverse wave and a longitudinal wave?
Tranverse wave - The oscillations are perpendicular (at 90°) to the direction
of travel.
Longitudinal wave - The oscillations
are parallel to the direction of travel
What do waves do?
Waves transfer energy from one
place to another.
They do this without any matter
being transferred.
What is the definition of frequency?
Frequency is the number of waves
passing a point in 1 second. It is
measured in Hertz (Hz).
What is the definition of wavelength?
The wavelength is the distance from
one part of a wave the next identical
part
What is the amplitude of a wave?
The amplitude of a wave is the maximum displacement of a point on a wave away from its undisturbed position.
The bigger the amplitude the more energy the wave carries.
What is the period of a wave?
The period of a wave is the time it
takes for one wave to pass a fixed point (or the time it takes to complete one
cycle)
Describe how you would measure the
speed of sound in air.
1 – Have 2 people stand far apart and have one
person make a loud noise (fire a gun etc).
2 – The other person starts a stopwatch when
they SEE the gun fired and stops it when they
HEAR the noise.
3 – Calculate the speed using the equation:
speed = distance ÷ time
Describe how you would measure
the speed of ripples on the surface of
water.
1 – Fill a tray with water.
2 – Measure the length of the tray.
3 – Create ripples on the surface at one end
4 – Measure the time it takes for a ripple to travel
from one end to the other.
5 - Calculate the speed using the equation
speed = distance ÷ time
What are electromagnetic waves
and how fast do they travel?
Electromagnetic waves are transverse
waves that transfer energy from the
source of the waves to an absorber.
How are electromagnetic waves made?
Changes in atoms and the nuclei of
atoms can result in electromagnetic
waves being generated over a wide
frequency range.
Gamma rays originate from changes
in the nucleus of an atom.
What is the wave equation?
Wave speed = frequency x wavelength
v = f x λ
What is the order of the EM spectrum?
Radio waves
Micro waves
Infra red
Visible light
Ultraviolet
X– rays
Gamma rays
What part of the EM spectrum has
the longest wavelength and which part has the highest frequency?
Longest wavelength is radio waves
Highest frequency is gamma rays
What 4 things can happen when an
EM wave hits a surface?
The EM waves can be…
Reflected
Refracted
Transmitted
Absorbed
What is refraction and why does
it happen?
Refraction is the change of direction that happens when light crosses a boundary from one medium to another at an angle.
It happens because there is a change of speed as it goes from one medium into another.
One side of the wave front crosses first and it either speeds up or slows down
What are some uses of each part
of the EM spectrum?
Electromagnetic waves have many practical applications.
For example:
1 - radio waves – television and radio
2 - microwaves – satellite communications, cooking food
3 - infrared – electrical heaters, cooking food, infrared cameras
4 - visible light – fibre optic communications
5 - ultraviolet – energy efficient lamps, sun tanning
6 - X-rays and gamma rays – medical imaging and treatments
