Waves Sound And Light Flashcards
What do waves do? How are they produced?
They transfer energy from one point to another. They are produced as a result of vibrations
Give 2 examples of longitudinal waves?
Sound
Seismic waves
Give 2 examples of transverse waves?
Water waves
Electromagnetic waves
What is a longitudinal wave?
This wave is when particles vibrate parallel to the direction of the wave
What is a transverse wave?
Wave that causes particles to vibrate at 90° to the direction of the wave
Give 2 examples that show how waves carry energy?
Visible light causes things to heat up
Water waves can generate electricity
Give 3 characteristics of waves?
Frequency
Wavelength
Amplitude
What is frequency?
The number of complete waves passing a fixed position in a second
Give unit used for frequency?
Hertz
What is wavelengths?
The distance between 2 consecutive crests or troughs
What unit are wavelengths measured in?
Metres
What is amplitude?
The greatest displacement of the wave from its undisturbed position
What unit is amplitude measured in?
Metres
How do you measure wavelengths in longitudinal waves?
Distance between 2 consecutive compressions ( compressed waves ) or rarefactions ( spaced out waves )
Give the ‘wave’ equation?
Wave speed = Frequency X Wavelength
v = f X (upside down y)
What is reflection?
This is when plane waves approach a barrier, which prevents the waves going over the top. The incident waves are then reflected and become reflected waves
What is refraction?
The bending of waves at a boundary, because the speed has changed
as the waves hit the boundary at an angle
What is ultrasound?
Sound that is too high a frequency for us to hear
What is dispersion?
This when light rays are refracted in a more optically dense medium, such as a prism, and the Rays then split in to the light spectrum
What is the critical angle?
When the Ray is just totally internally reflected, the angle between the Ray and the normal inside the block becomes known as the critical angle
What is internal reflection?
When light rays travelling a more optically dense medium, hit its edges at an angle, known as the critical angle. This causes the light Ray to reflect off the edge and back in to the medium
What is the focal length of a lens?
The distance between the centre of the lens and the image
Give 3 uses of ultrasound?
Sonar
Pre natal screening
Removal of kidney stones
What does Radar stand for?
RAdio Detection And Ranging
What is radar used for?
It is used to determine the range, altitude, direction or speed of objects by detecting the reflected radio waves or microwaves
What is an incident Ray?
The Ray of light traveling towards the mirror
Give 2 uses of plane mirrors?
In looking glasses (mirrors)
Periscopes
What is the electromagnetic spectrum?
These are electromagnetic waves that have common properties
Give 3 properties of electromagnetic waves?
Can travel in vacuum
Travel at same speed in a vacuum
Are transverse waves
Name 4 electromagnetic waves?
Gamma
X Ray’s
Infrared
Microwaves
Name 3 electromagnetic waves which are also known as ionising radiation?
X Ray’s
Gamma rays
Ultraviolet rays
Give a use of gamma rays? Give a danger?
Can destroy viruses and bacteria in food industry by irradiating food
Can cause cancer
Give a use of X Ray’s? A danger?
Can be used in body scanning
Can cause cancer
Give a use of ultraviolet rays? A danger?
Can be used to detect forgeries in banknotes
Prolonged exposure can cause skin cancer
Give a use of infrared rays? A danger?
Can be used in toasters, grills, etc, as they cause objects to heat up
Can burn the skin, such as sunburn
Give a use of microwaves and radar waves? A danger?
Can be used for mobile phone and satellite transmissions
Pose a hazard to us because they are so easily absorbed by water molecules, and our bodies contain a lot of water
Give a use of radio waves?
Used extensively for communication
Name the 2 types of waves?
Longitudinal
Transverse
