Properties of waves

What do waves transfer

Energy and information without transferring mass

What are the differences between longitudinal and transverse waves?

• Longitudinal waves vibrate parallel to the direction of travel (sound)

• Transverse vibrate perpendicular to the direction of travel (light)

• Longitudinal waves consist of compressions and rarefactions

• Transverse consist of peaks/crests and troughs

What is the definition of amplitude, wavefront, frequency, wavelength and time period?

• Amplitude: The maximum displacement of particles from their equilibrium position.

• Wavefront: An imaginary surface representing points of a wave that are at the same point in their cycle.

• Wavelength: The distance between a particular point on one cycle of the wave and the same point on the next cycle.

• Frequency: The number of waves passing a particular point per second. Is measured in Hertz (Hz).

• Time Period: The time it takes for one complete wave to pass a particular point.

What is the doppler effect?

• When a car is not moving and its horn sounds, the sound waves the observer receives are a series of evenly spaced wavefronts.

• If a car is moving, wavefronts of the sound are no longer evenly spaced.

  • Ahead of the car wavefronts are compressed as the car is moving in the same direction as the wavefronts. This creates a shorter wavelength and a higher frequency to the observer.

  • Behind the car wavefronts are more spread out as the car is moving away from the previous wavefronts. This creates a longer wavelength and a lower frequency to the observer.

What are the qualities of reflection?

• All waves can be reflected

• frequency, wavelength and speed are unchanged

What are the qualities of refraction?

• All waves can be refracted, which is when the speed of a wave changes when it enters a new medium

• If a wave enters a denser medium, its speed decreases, and the wave bends towards the normal. Wavelength decreases as frequency stays the same, and velocity decreases (velocity = frequency x wavelength)

• If a wave enters a less dense medium, its speed increases, and it bends away from the normal. Wavelength increases as frequency stays the same, and velocity increases.