Physics // Lightwaves and Soundwaves

What do lightwaves do?

Reflect and Refract

Angle of incidence =

= Angle of reflection

Large wave amplitude

Louder the wave

Greater Frequency

Higher pitch of the waves

Do wave speeds change?

The speed is constant

Amplitude

The distance from the equilibrium position to the maximum displacement

Wavefront

A surface containing points affected in the same way by a wave at a given time

Wavelength

The distance between a point on one wave and the same point on the next wave

Time Period

The time taken for one complete wave to pass a fixed point

Does light slow down in thicker materials?

Yes.

Transverse waves

Has peaks and troughs
Vibrations are at right angles to the direction of travel
An example is light

Longitude wave

Consists of compressions (Particles pushed together) and rarefactions (Particles moved apart)
Vibrations are in the same direction as the direction of travel
An example is sound

Refractive Index

Speed of light in vacuum divided by the speed of light in medium
The refractive index, given the symbol n, can also be calculated by the formula : n = sin i divided by sin r

The refractive index

The refracted index is defined as the ratio of the speed of light in air or in a vacuum to the speed of light in another medium

Refraction

Refraction is the bending of light which occurs when it enters a different material. The light travels at different speeds in different media, Media in which light travels slower are said to be optically dense. It is the changing speed that causes light to refract.

Critical angle

Smallest angle of incidence = Where light is internally reflected

The critical angle c can be related to the refractive index

n = 1 / sin c

TIR

total internal reflection, Occurs when the angle of incidence is greater than the critical angle and the light reflects back into the medium