Flashcards
Waves
Flashcards do conjunto (23)
- 1We use to waves to transfer energy and information....
- 2Transverse wave -Oscillations of the particles are perpendicular to the direction in which the wave travels
- 3Longitudinal wave the oscillation of the particles is parallel to the direction of the wave -Made up of compressions and rarefactions
- 4Electromagnetic waves -Transverse waves -Can travel through a vacuum -no particles moving in the wave, oscillations in electric fields -Light and RadioMechanical Waves
-Transverse or longitudinal
-travel through a medium
-spring, sound waves - 5—Speed=frequency x wavelength
- 6Frequency(Hz)the number of wave crests passing a point in one second
- 7Wavelengththe distance from one crest/trough to the next crest/trough
- 8AmplitudeThe depth from the trough to the position at rest
- 9Amplitude for longitudinal- distance from the middle of one compression to the middle of the nextFrequency for longitudinal-number of compressions passing a point in one second
- 10The normal at a point on a surface is a line drawn perpendicular to the surface
- 11The law of reflectionthe angle of incidence is equal to the angle of reflection
- 12Image in a plane mirror is: -virtual -upright -same size as the object -same distance behind the mirror as the object is in frontA real image can be formed on a screen, as the light rays that produce the image actually pass through it
- 13Virtual Imagecannot be formed on a screen, as light rays that produce the image only appear to pass through it
- 14Refraction -the change of direction of a light ray when it crosses a boundary between to substancesThe wavelength changes causing a change in direction, frequency stays the same
- 15When light enters a more dense substance, it slows down and the ray goes toward the normalWhen it enters a less dense substance, it speeds up and the ray goes away from the normal. If the wave is travelling along the normal it doesn't change direction
- 16Refraction of light
- 17Violet light is refracted the most Red light is refracted the leastdispersion is when white light is shown through triangular glass and a spectrum is produced
- 18Diffraction- the spreading out of waves when they pass through a gap or round the edge of an obstacleThe narrower the gap, the greater the diffraction
- 19—If radio waves do not diffract enough when they go over hills, radio and TV reception is poor
- 20Sound is caused by mechanical vibrations in a substance. Travels fastest in solids and slowest in gases-cannot travel through a vacuum
-longitudinal
-range frequency for humans: 20Hz- 20000Hz - 21sound can be reflected to produce echoes -hard, flat surfaces reflect -soft absorbSound can be refracted
-takes place a t boundaries between different temp.
-can be diffracted - 22The higher the frequency, the higher the pitch The higher the amplitude, the louder the waveVibrations created in an instrument when it is played produce sound waves
- 23Tuning forks produce 'pure' wave forms Quality of the note depends on the waveform...