What is a wave?
An oscillation (vibration) that transfers energy from one place to another.
What is a transverse wave?
A wave that oscillates at right angles (perpendicular) to the direction that energy is transferred.
What are some examples of transverse waves?
Water waves, light, (radio waves, microwaves, etc.)
What is a longitudinal wave?
A wave that oscillates in the same direction that energy is transferred.
What are examples of a longitudinal waves?
Sound-waves, seismic, ultrasound
What is the highest point on a transverse wave called?
The peak (or crest).
What is the lowest point on a transverse wave called?
The trough.
What is the point on a longitudinal wave where it is spread out called?
A rarefaction.
What is the point on a longitudinal wave where it is close together called?
A compression.
What is wavelength?
The distance between one point on a wave and the same point on the next wave. It is often easiest to measure from the peak or trough of one wave to the other.
What is amplitude?
The height from the peak or trough to the middle (always equal).
Independant of wavelength
What are 2 ways you can calculate the wave’s speed?
- v=fλ
- v=d/t
Velocity (ms-1), frequency (Hz), time (s), wavelength (m), distance (m)
What is frequency?
The number of waves that pass a point in a second. (Hz)
What is the formula for frequency?
f=N/t - frequency (Hz) = number divided by time (secs)
In what environment do sound waves travel the quickest?
In dense solids, the close-together particles can transfer the energy faster as they vibrate.
What is a light year?
The distance traveled by light in a year.
How would you conduct a refraction experiment?
- Mark the normal (perpendicular to middle of glass block)
- Shine rays of light at equal angle intervals from the normal (one on each side)
- Mark the angle of incidence and refraction.
- If the angle of refraction lines up roughly with the opposite previous angle of incidence, it’s right.
How does shining light onto a glass block work?
The angle of refraction is equal to the angle of incidence.
The angle of incidence and refraction are always measured between the ray of light and normal.
What are the order of lightwaves from shortest to largest wavelengths?
(Top to bottom)
- gamma rays
- x rays
- ultraviolet
- visible light
- infrared radiation
- microwaves
- radiowaves
What are the order of lightwaves from largest to shortest wavelengths?
(Top to bottom)
- radiowaves
- microwaves
- infrared radiation
- visible light
- ultraviolet
- x-rays
- gamma rays
What are the types of waves, their dectector then their usage?
1st half (largest to shortest, top to bottom)
- Radio waves, aerial, communications
- Microwaves, microwave radiometers, heating food/water
- Infrared radiation, electronic detectors, detector in security
- Visible light, electronic devices (e.g. LEDs)/eyes, sight and photography
What are the types of waves, their dectector then their usage?
2nd half (largest to shortest, top to bottom)
- Ultraviolet, photodiodes, water purification
- X-rays, spectrometers, medical imaging
- Gamma rays, semiconductor detectors, cancer treatment
What is diffraction?
The spreading out of waves as they pass through a gap or edge of obstacle.
Frequency and wavelength remain constant after diffraction,.
The wave changes direction by spreading out and bending.
What are the two diffraction rules?
- The greater the wavelength (and the lower the frequency) the greater the angle of diffraction.
- The narrower the gap the greater angle of diffraction.
