🌊 Optics

Front 1

Phenomena that support wave nature of light

Back 1

Interference, superposition, diffraction, polarisation

Front 2

Phenomena that support particle nature of light

Back 2

Photoelectric effect, Compton effect

Front 3

Who suggested that light had dual nature

Back 3

De broglie

Front 4

What could rectilinear propagation of light NOT explain

Back 4

Couldn't explain why light(when allowed to pass through slit whose wavelength was in the range of that of light) tended to spread into the regions of otherwise geometrical shadows.

Front 5

Definition of wavefront

Back 5

Huygen was the one who said that light travels in the form of wavefronts.

It is defined as the continuous locus of all such particles of the medium which are vibrating/oscillating

in the same phase at any instant.

It is a surface of constant phase.

Hint 5

Lpcus

2 points

Front 6

Phase speed

Back 6

The speed with which the wavefront moves outwards from the source.

Front 7

Types of wavefronts generated depends on the

Back 7

Source of disturbance

Front 8

Types

Back 8

Spherical

Cylinderical

Plane

Front 9

Ray

Back 9

The energy of a wave travels in a direction perpendicular to the wavefront

Ray is an arrow drawn perp to a wavefront in the direction of propagation of wave.

It represents the path along which the wave travels.

Front 10

A collection of rays of light is called

Back 10

A beam of light

Front 11

Cylinderical wavefront

Back 11

When the source of light is linear in shape(like a fine rectangular slit), the wave front generated is cylinderical in shape.

Front 12

Spherical wavefront

Back 12

When the source of light is a point src, the wave front generated is spherical in shape

Diagram

Front 13

Plane wavefront

Back 13

As a spherical/cylinderical wavefront progresses, its curvature decreases progressively. So, a small portion of such a wavefront at a large distance from the source will appear to be a plane wave front

Front 14

Huygen's princilple

Back 14

Each point on a wave front is a source of secondary waves(spherical), which add up to give a wavefront at any later time.

Front 15

Polarisation of wave

Back 15

The phenomenon of restricting vibrations of a transverse wave to just one direction in a plane(plane of vibration) perpendicular to the direction of propagation.

Front 16

Unpolarized wave(light)

Back 16

When the vibrations in a transverse wave are in all possible directions in a plane perpendicular to the direction of propagation, the wave is said to be unpolarized.

Front 17

Law of Malus

Back 17

I=I⁰cos²∅ where theta is the angle between the planes of transmission of the polariser and the analyser.

Where I is the intensity of the light transmitted by the analyser and Io is the maximum intensity transmitted by the analyser i.e. when the planes of transmission of polariser and analyser are parallel to each other (i.e when ∅=0⁰)

Front 18

Brewster's law

Back 18

U(refractive index of the transparent medium)=tan i(p)

Where I(p) is the angle of polarisation/Brewster's angle

When ordinary unpolarized light is incident on a transparent medium, the reflected ray is found to be partially plane polarised. The extent of polarisation depends on the angle of incidence.

At a particular angle of incidence, the reflected ray is found to be completely polarised. That angle of incidence is called angle of polarisation/Brewster's angle.

Front 19

Relationship between path difference and phase difference∅

Back 19