TOPIC 4 - WAVES Flashcards
what are waves
Waves transfer energy and information without transferring matter
Transverse vs longitudinal waves
- Longitudinal waves move parallel to direction of energy transfer
- Transverse waves move perpendicular to direction of energy transfer
- Longitudinal have compressions and rarefactions
- Transverse have peaks and troughs
- Longitudinal waves move in solids liquids gases
- Transverse waves move in solids only
What is frequency
Number of wave cycles per second
What is wavelength
Distance peak to peak or compression to compression
What is period
Time taken to complete one wave cycle
Equation linking time and frequency
Time = 1/f
Frequency = 1/T
What is amplitude
Maximum displacement a point moves from rest position
Equation for wave speed
frequency x wavelength
or
distance/time
What can happen to waves when meeting a boundary?
- Reflected
- Refracted
- Transmitted
- Absorbed
What is reflection
When wave ‘bounces off’ boundary and stays in their original medium.
What is refraction
When wave changes speed and direction betweem 2 materials of different densities.
What happens to light ray if moving from a less dense to a more dense medium
It slows down and refracts towards normal.
What types are waves are sound waves
Longitudinal
What happens when sound waves are passed through liquids and gases?
particles vibrate back and forth as wave passes through.
What happens when sound waves are passed through solids?
Some energy is reflected, transmitted or absorbed. The sound wave causes changes in pressure on surface of the sold. It causes the particles in solid to vibrate (vibrations in solid can be longitudinal/transverse)