| Difference between transverse and longitudinal waves | Transverse wave oscillations are perpendicular to the direction of energy transfer, whilst longitudinal wave oscillations are parallel to the direction of energy transfer |
| Give examples of transverse waves | Electromagnetic waves, ripples in water, wave on a string |
| Give examples of longitudinal waves | Sound waves, shock waves |
| Rest position definition | Undisturbed position of particles or fields when they are not vibrating |
| Displacement definition | Distance that a certain point in the medium has moved from its rest position |
| Peak definition | Highest point above the rest postition |
| Trough definition | Lowest point below the rest position |
| Amplitude definition | Maximum displacement of a point of a wave from its rest position |
| Wavelength definition | Distance covered by a full cycle of the wave usually measured from peak to peak or trough to trough |
| Time period definition | Time taken for a full cycle of the wave usually measured peak to peak or trough to trough |
| Frequency definition | Number of waves passing a point each second |
| Method to measure speed of soundwaves in air | Attach a signal generator to a speaker you can generate sounds with specific frequencies
Set up oscilloscope so waves from microphones are shown as separate waves
Start with microphones next to the speaker then move one away until the two waves are aligned by are one wavelength apart
Measure distance between microphones to get one wavelength
Use an equation to calculate speed of waves
Results should be around 330 m/s |
| Method to measure speed of ripples on a water surface | Use a signal generator attached to a ripple tank to create waves of a set frequency
Use a lamp to see wave crests on a screen below the tank [wave shadows should be same size as actual wave crests
Distance between each shadow line is equal to one wavelength
Measure the distance between 10 wavelengths apart and then divide by 10 to find the average wavelength
Use an equation to calculate the speed of the waves |
| What is the rule for all reflected waves? | Angle of incidence = Angle of reflection |
| What is specular reflection? | When a wave is reflected in a singular direction by a smooth surface |
| What is diffuse reflection? | When a wave is reflected in lots of different directions by a rough surface |
| Effect of reflection at material interfaces | The wave is reflected at the same angle it meets the material at |
| Effect of absorption at material interfaces | Energy is transferred to the material's energy stores |
| Effect of transmission at material interfaces | Waves travel through the material and are refracted on the other side |
| Method for investigating light refraction on different substances | Place transparent rectangular block on a piece of paper and trace around it
Use ray box to shine a ray of light at the middle of one side of a block
Trace incident ray and mark where it emerges on other side of block
Remove block and join incident ray with reflected ray
Draw the normal at the point where the IR entered the block
Measure the angle between the IR and normal, and the angle between the refracted ray and the normal
Repeat using different blocks of material keeping the incident angle the same |
| Independent, dependent and control variables for RP 9 | Independent- Type of block material
Dependent- Angle of refraction
Control- Incident angle |
| Conclusion for RP 9 | The angle of refraction changes for different materials due to their optical densities |
| Method to investigate light reflection on different substances | Draw a straight line across a piece of paper
Place an object so it lines up to the line
Shine a ray of light at the surface and trace the incoming and reflected light beams
Draw the normal and then measure the angle of incidence and the angle of reflection
Make note of the width and brightness of the reflected ray
Repeat the experiment but changing the object each time |
| Independent, dependent and control variables for RP 10 | Independent- object type
Dependent- angle of incidence and angle of reflection
Control- angle of incidence |
