Light and Sound Flashcards
What are the 2 types of wave?
Transverse and longitudinal
What are transverse waves used to show?
Light
What are longitudinal waves used to show?
Sound
What do waves transfer?
Energy (sometimes information) without transferring matter
What is the highest point of a wave called?
A crest
What is the lowest point of a wave called?
A trough
What is the amplitude of a wave?
Height of wave from crest/trough to central x axis point
What is the wavelength of a wave?
The distance between 2 successive crests/troughs
What is frequency measured in?
Hertz
What is the normal?
An imaginary line 90 degrees to the mirror
What is the 1st law of reflection?
Angle of incidence = angle of reflection
What is lateral inversion?
The apparent reversal of left and right in a mirror
What is refraction?
When the direction of a wave is changed as it passes a median which has a different speed
What is the formula for refractive index?
Sin(angle I )/ Sin(Angle R)
What is the refractive index of glass?
1.5
What is the refractive index of water?
1.3
What are the units of refractive index?
Refractive index has not units!
What is Total Internal Reflection?
When the angle of incidence is greater than the critical angle and all the light is reflected
What is the critical angle?
When the angle of refraction is at 90o and angle of incidence is less than this, so angle of incidence now critical angle.
Where can we see use of Total Internal Reflection?
Submarine periscopes and optical fibres
What is diffraction?
When waves are evenly dispersed and scattered after passing through a gap or pushing through an obstacle.
What are concave lenses?
Diverging, so when parallel light rays pass through, the refracted rays diverge
What are convex lenses?
Converging, so when parallel light rays pass through, the refracted rays converge at the principal focus
Do we draw lines on a virtual ray?
No
What is a virtual ray?
A path along which light appears to travel travel but has actually not
What is a real ray?
A path light has actually traveled down
What are the spectrum of colours?
Red, Orange, Yellow, Green, Blue, Indigo, Violet
What is the speed of light?
3x10^8m/s
What is the speed of sound?
343m/s
What are the 7 wave types?
Radio, micro, infra-red, light, UV, X-ray, gamma
What is the Doppler Effect?
The apparent change in the frequency of a wave caused by the wave source and the observer
What is the symbol for frequency?
Lamda (Upside down y)
In terms of speed and sound, what is velocity equal to?
Wavelength x Frequency
What would happen if you double frequency?
The pitch would go up by an octave
What does the loudness of sound depend on?
Amplitude
What does the pitch of sound depend on?
Frequency and wavelength
