Waves Flashcards
What is amplitude?
The displacement from the rest to the crest
What is wavelength?
The length of a full cycle (crest to crest)
What is frequency?
The number of complete waves produced per second
What does Hz mean?
Wave per second
If the angle of reflection is 50 degrees, what is the size of the angle of incidence?
50 degrees
Where is the normal?
A 90 degree angle from the surface of the mirror
What makes an image virtual?
When it appears to be somewhere (behind the mirror) but in reality, is not
What are transverse waves?
Vibrations perpendicular to the energy transfer of the wave (e.g. Light, EM waves, ripples)
What are longitudinal waves?
Vibrations parallel to the direction of energy transfer
How do you find frequency? (Hz)
Speed (m/s) / wavelength (m)
What is diffraction?
When waves spread out at the edges when they pass an obstacle
What causes a wave to greatly diffract?
A narrow gap or a long wavelength
What happens if the gap and the wavelength are the same size?
The wave fully diffracts
How does refraction work?
The wave passes through a medium denser than air and slows down, changing direction
What happens if the waves meet the medium along the normal?
They slow down but do not refract
What is the range of EM wave size?
10^-15 - 10^4
____ frequency, ____ wavelength
Higher frequency, shorter wavelength
Radio waves diffract. What does this make them useful for?
Sending waves around the world or obstacles by bouncing them off the Earth’s curved surface
Mnemonics for remembering the electromagnetic spectrum
Rabbits Mate In Very Unusual eXpensive Gardens
Granny’s Xbox Uses Volts In My Room
Why are microwaves good for satellite communication and mobile phones?
They can easily pass through the Earth’s atmosphere
What is an echo?
A reflected sound wave
How do you find wave speed?
Frequency * wavelength
(V = f*λ) [lambda]
What is a mechanical wave?
One that must travel through a medium
What is an electromagnetic wave?
One that doesn’t need to travel through a medium
Uses of radio waves
Television
Radio
Mobile phones
Bluetooth
Uses of micro waves
Cooking
Mobile phone calls
Satellite dishes
Uses of infrared waves
Optical fibre communications
Toasters
Heaters
Grills
Uses of light waves
Fibre optic cables
Digital cameras
Which wave may be used to send a signal to a satellite through the ionosphere?
Microwave
What will happen to the frequency, wavelength and speed of a reflected microwave?
Wavelength - decrease
Frequency - increase
Speed - same
