Waves Flashcards
What are the two types of waves?
Transverse - at right angles to the direction of energy transfer
longitudinal - parallel to the direction of energy transfer
Frequency
The number of waves passing a fixed point per second measured in hertz
Amplitude
The maximum height of a wave from the middle of a wave to its peak is trough.
Wavelength
The distance from one point on a wave to the equivalent point in the next wave in metres
Period
The time taken for one complete oscillation in seconds
Wave speed
The speed at which the energy is transferred
Ripple tank experiment
- Time how long it takes one wave to travel the length of the tank using speed = distance/time
- Count then number of waves passing a fixed point in a second to find the frequency
- Use a ruler to measure the peak to peak to estimate the wavelength
- Use a stroboscope to make the same measurements and compare the results
Control: water depth
Errors: stroboscope is more accurate
Speed and wavelength are … proportional
Directly
What changes when waves are transmitted from one medium to another?
Speed and wavelength
Frequency doesn’t change as the same number of waves are still being produced by the source per second
Refractive index
The way in which a material affects refraction.
The bigger the refractive index, the slower the light travels through the material.
Refraction is due to
The difference in the wave speed in the different media
When a light wave enters at an angle a medium in which it travels slower…
The first part of the light wave to enter the medium slows down
The rest of the wave continues at the higher speed
This caused the wave to change direction, towards the normal
Investigating reflection and refraction
- Set up the equipment
- Draw around the semicircular block
- Mark the position of the light at the start, at the end, and where it enters and exits the block
- Remove the block and connect the marks to show the light rays
- Repeat on a new piece of paper for a range of incident angles
- Repeat the experiment with blocks made of different transparent materials
What is the range of human hearing?
20Hz - 20kHz