Unit 6: Geometric and Physical Optics

waves are a type of wave that consists of oscillating electric and magnetic fields that travel through space at the speed of light.They are produced by the acceleration of charged particles and include radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays.

The phenomenon of superimposition of two or more waves having the same frequency emitted by two coherent sources.

It can be categorized by its frequency. The full range of waves is called the electromagnetic spectrum.

It is defined as the interference or bending of waves around the corners of an obstacle or through an aperture into the region of the geometrical shadow of the obstacle/aperture.

A diffraction pattern will also form on the screen if the barrier contains only one slit.

The incident light on a barrier that contains two narrow slits, separated by distance d. On the right there is a screen whose distance from barrier L, is much greater than d.

d sinθ = m λ

d sinθ = (m+1/2) λ

• where, m = 0, 1, 2, 3, etc.

• λ = wavelength of light

• d = distance

The angle that the incident beam makes with the normal

The angle that the reflection makes with the normal

The angle that the transmitted beam makes with the normal

The incident, reflection, and transmitted beams of light all lie in the same plane.

The relationship between the incident and reflected ray:

angle of incidence = angle of reflection

n = c/v

• c = speed of light (3*10^8 m/s)

• v = speed of light in a particular medium

• n = refractive index

• n 1 sin θ′1 = n2 sin θ′2 If n2>n1, the beam will bend/refract toward the normal.

• If n2<n1, the beam will bend away from the normal.

  • Here, n1 and n2 are the refractive indexes in respective mediums.

it occurs when:

• n1> n2 and θ1> θc, where, θc = sin−1 (n2/n1)

• θc is the critical angle.

• n1 and n2 are the refractive indexes in respective mediums.

is an optical device that forms an image by reflecting light.

Our image is behind the mirror and stands at an equal distance as we stand before the mirror.

is a mirror that’s curved in such a way that its surface forms part of a sphere.

F = R/2 where,

• F = focal length (the focal length of an optical system is a measure of how strongly the system converges or diverges light).

• R = radius of curvature (the radius of curvature is the radius of a hollow sphere of which the mirror/spherical mirror is a part).

A mirror whose reflective side is caved in toward the center of curvature.

A mirror whose reflective side curving away from the center of curvature.

1/so + 1/si =1/ f

• so = object distance

• si = image distance

• f = focal length

M = hi/ho = -si/so

• M = magnification

• hi = height of the image

• ho = height of the object

• si = image distance

• so = object distance

Bi-convex lens

Bi-concave lens

P = 1/f

• P = power of the lens

• f = focal length of lens

is a form of energy that travels in a straight line when in one medium (material).

The continues of colors that make up with light.

Using light rays to determine how light behaves when it strikes an object.

is a line and arrow representing the direction and straight-line path of light.

An image which light actually comes from the image

an image which light does not arrive at or actually come from the image location, light only appears to come from the image

The centre of the sphere whose surface was used to make an image

This is a line through the centre of curvature which runs through midpoint of mirror.

is the point at which lights rays parallel to principal axis converge when reflected.