Refraction of Light Lecture Notes

Comprehensive vocabulary flashcards covering the principles of refraction, refractive indices, lens properties, and the lens formula based on Physics Chapter 9 notes.

Refraction of Light

The bending of light at the interface of two different mediums.

Optical rarer medium

A medium in which the velocity of light is more; for example, air or vacuum.

Optical denser medium

A medium in which the velocity of light is less; for example, glass is denser than air.

Refractive Index

A constant representing the amount or extent of bending of light when it passes from one medium to another, defined as the ratio of the sine of the angle of incidence to the sine of the angle of refraction.

Relative Refractive Index

The refractive index of a medium with respect to another medium, expressed as $n_{12} = \frac{V_2}{V_1}$ where $V_2$ is the speed of light in medium 2 and $V_1$ is the speed of light in medium 1.

Absolute Refractive Index ($n_m$)

The refractive index of a medium with respect to air or vacuum, expressed as $n_m = \frac{c}{V}$, where $c$ is the speed of light in air and $V$ is the speed of light in the medium.

Thin lens

An optical system with two spherical surfaces close enough together that the distance between them can be neglected.

Converging lens (Convex lens)

A lens that is thicker at its centre than at its edges, typically having a positive focal length ($f$).

Diverging lens (Concave lens)

A lens that is thicker at its edges than at the centre, typically having a negative focal length ($f$).

Optical centre ($C$)

The central point in the lens through which an incident ray passes undeviated.

Principal axis

The line joining the two centres of curvatures of the lens surfaces and passing through the optical centre.

Aperture

The effective width of a lens through which refraction takes place.

Focus ($F$)

The point on the principal axis where rays moving parallel to the principal axis converge (in a convex lens) or appear to diverge from (in a concave lens) after refraction.

Focal Length

The distance from the optical centre ($C$) to the focus ($F$).

Lens formula

The equation relating object distance ($u$), image distance ($v$), and focal length ($f$), expressed as $\frac{1}{v} - \frac{1}{u} = \frac{1}{f}$.

Linear magnification ($m$)

The ratio of the size of the image ($h'$) to the size of the object ($h$), also represented as $m = \frac{v}{u}$.

Power

The reciprocal of the focal length, measured in dioptre ($D$).