P14 Mechanical waves Flashcards
What is a transverse wave?
Oscillations are perpendicular to the direction of energy transfer
What is a longitudinal wave?
Oscillations are parallel to the direction of energy transfer
Amplitude
Maximum displacement of a point on a wage from its undisturbed position
Unit for amplitude
meteres
Frequency
Number of waves passing a fixed point per second
Unit for frequency
Hertz
Period
Time taken for one complete wave to pass a fixed point
Unit for a peroid
Seconds
Wavelength
Distance from one point on a wave to the equivalent point on the next wave
Unit for wavelength
Meteres
Wave speed
Distance travelled by each wave per second, and the speed at which energy is transferred by the wave
Unit for wavespeed
meters per second
Example of a transverse wave
Electromagnetic waves
Example of a longitudinal wave
Sound waves
Wave speed equation
Wave speed(m/s) = frequency(Hz) X wavelength(M)
How are frequency and period related in equation?
Period = 1 / Frequency
What is a compression?
Area in a longitudinal wave where the particles are squashed close together
What is rarefaction?
Area in a longitudinal wave where particles are pulled apart
What property of a wave stays the same when it travels from one medium to another?
Frequency
What rule do waves follow when they reflect off a surface/
Angle of incidence = angle of reflection
What happens when waves are transmitted at a boundary between two substances?
They carry on moving at a different speed
What happens when waves are absorbed by a substance?
Energy of the wave is transferred to energy stores of the substance
Absorption (waves)
The energy of the waves in transferred to energy stores of the substance they travel in to
e.g when food is heated in a microwave
Reflection
The waves bounce back
Refraction
The waves change speed and direction as they cross the boundary
Transmission
The waves carry on moving once they have crossed the boundary, but may be refracted
