P11 Wave Properties Flashcards
Transverse waves
The oscillations are perpendicular to the direction waves transfer energy. All electromagnetic waves are transverse waves.
e.g. light wave. Radio wave, microwave, ripples on the surface of water, waves on a string, seismic S-waves
Longitudinal waves
The oscillations(compressions and rarefactions) are parallel to the direction waves transfer energy
e.g. sound wave, ultrasound wave, infrasound wave
Peak
Top of a wave
Trough
Bottom of a wave
Amplitude
The amplitude of a wave is the maximum displacement of a point on the wave from its undisturbed position. The bigger the amplitude of the waves, the more energy the waves carry.
Wavelength
The distance from a point on the wave to the equivalent point on the adjacent wave.
Frequency
Number of waves past a fixed point per second
Period
Time taken for each wave to pass a fixed point
Period equation
1/frequency(hertz)
Wave speed equation(for waves of constant frequency)
Wave speed = frequency x wavelength
What is a ripple called in a ripple tank
Each ripple in a wave is called
a wavefront because it’s the front of each wave as it travels across the water surface.
Refraction
Change of direction in which plane waves(straight waves) are travelling when they cross a boundary between one medium and another medium. .
What happens at a boundary between two different materials?
Waves can be transmitted or absorbed.
e.g. Light is transmitted by ordinary glass.
Food is heated in microwave ovens.
How to produce sound waves
Vocal cords vibrate and produce sound waves when you speak.
Any object vibrating in air makes the layers of air near the object vibrate, which makes the layers of air near them vibrate. The vibrating object pushes and pulls repeatedly on the air
This sends out vibrations of air in waves of compressions and rarefractions. When the waves reach the ears, they make eardrums vibrate in and out so they hear sound.
Speed of sound waves
It increases with increasing temperature and is 340m/s at 15C
Where are all angles measured?
All angles are measured between the ray and the normal.
Angle of incidence
Angle a ray comes in at
When light waves travel from a faster material to a slower one…
The light refracts and bends towards the normal
When light waves travel from a slower material to a faster one…
The light refracts and moves away from the normal
How does refraction affect frequency?
In refraction, the frequency of the waves doesn’t change.