P1 - Waves Flashcards
What is a transverse wave?
These waves vibrate perpendicular to the direction of energy transfer of the wave.
What can waves be used for?
Energy and information transfer.
What type of wave is an electromagnetic wave?
Transverse
What is a longitudinal wave?
The wave vibrates parallel to the direction of energy transfer of the wave.
What type of wave is a sound wave?
Longitudinal
What type of wave is a mechanical wave.
A mechanical wave can be transverse of longitudinal.
What is needed for a mechanical wave to vibrate?
A medium
How fast do EM waves travel?
300,000,000 m/s
Give three examples of EM waves.
Visible light, radio, microwave
What are the vibrations of a longitudinal wave also known as?
Compressions
What is the amplitude of a wave?
The height or depth of a wave from the position of rest.
What is the frequency of a wave?
The number of waves that pass a point in one second.
What is a wave’s wavelength?
The distance from one crest to another.
What is the formula for wave speed, wavelength and frequency?
v=f λ
What is the unit of frequency?
Hertz
What is the normal in a diagram showing light rays?
A line drawn at a point perpendicular to the mirror.
What is an angle of incidence?
The angle between the incident ray and the normal.
What is an angle of reflection?
The angle between the reflected ray and the normal.
What is the law of reflection?
The angle of incidence equals the angle of reflection.
What is a plane mirror?
A perfectly flat mirror.
What is a virtual image?
An upright and laterally inverted image.
How is a real image formed?
Focusing light onto a screen.
What is refraction?
The change of direction of waves when they travel across a boundary.
What happens to a light ray when it travels from air to glass?
The angle of refraction is less than the angle of incidence. The ray travels towards the normal.
What happens to a light ray when travelling from glass into air?
The angle of refraction is more than the angle of impedance.
What is diffraction?
The spread of waves when passing through a gap or round the edge of an obstacle.
How does the width of the gap effect the diffraction of waves?
The narrower the gap is, the greater the diffraction.
Why can radio and TV reception be poor in hilly areas?
If the radio waves do not diffract enough, the waves won’t reach the aerial on a house.
How does diffraction effect optical imaging?
If light diffracts too much, the image is of poor quality.
How does diffraction effect ultrasonic imaging?
If the transmitter is too narrow, the waves spread out making the image unclear.
What is the range of human hearing?
20-20,000 Hz
What are sound waves?
Vibrations that travel through a medium.
What are echoes?
Sound waves reflected from a smooth, hard surface.
How can sound waves be produced?
Any object vibrating in air makes layers of air nearby vibrate.
What is the speed of sound?
330ms^1
How does air temperature affect the speed of sound?
The warmer the air, the greater the speed of sound.
Where does sound refraction take place in air?
The boundaries between layers of air at different temperatures.
Which way does sound reflect in the day and why?
In daytime, sound refracts upwards because the air near the ground is warmer than the air higher up.
What determines the pitch of a note?
The pitch of a note increases with the frequency of sound waves.
What happens to the loudness of a note as the amplitude increases?
The loudness of a note increases with the amplitude of the sound waves.
How are sound waves created by musical instruments?
Vibrations made by the instrument when it is played produce sound waves.
