Waves

f=1Tv=fλf=\frac{1}{T} \\ v=f\lambda

Light

Light is an example of a transverse wave in the electromagnetic spectrum.

Reflection

Plane Mirror

A plane mirror always produces an image that is:

  • virtual
  • laterally inverted
  • equal

Plane mirrors are flat. This means there is no distortion or scaling of the image. A virtual image is produced because the rays diverge but appear to converge behind the mirror.

Refraction

The refractive index is the ratio of the speed of light in a vacuum to the speed of light in another medium.

Snell's law is used to calculate the refractive index of a medium. Denser mediums will have a refractive index that is always greater than 1.

ni×sin⁡θi=nr×sin⁡θrn_i \times \sin \theta_i=n_r \times \sin \theta_r

The incident material is assumed to be a vacuum which means it has a refractive index of 1. Therefore, Snell's law can be simplified.

nr=sin⁡θisin⁡θrn_r=\frac{\sin \theta_i}{\sin \theta_r}

Total Internal Reflection

Total internal reflection requires 2 conditions to happen.

  • Light must be travelling from a denser medium
  • The angle of incidence must be greater than the critical angle

Refraction will not happen at the critical angle of a denser medium because the ray would refract at 90 degrees and stay within the medium.

Convex Lens

A convex lens bulges outwards. It is also known as a converging lens because it bends rays towards the principal axis.

Position Type Orientation Scale
d0>2fd_0 > 2fRealInvertedDiminished
do=2fd_o = 2fRealInvertedEqual
2f>do>f2f > d_o > fRealInvertedEnlarged
do=fd_o = f??Infinite
f>do>0f > d_o > 0VirtualUprightEnlarged