Light its nature and behaviour By Malik Shahroz

Light, Behavior and its Light, Behavior and its NatureNature

By; Malik Shahroz Akber

LightLightLight is a energy by which human eye is sensitive

OR Light is a natural agent which stimulates sight and makes things visible

LightLight

Without light, nothing is visible.

When you look at fish in the ocean, you are not seeing fish. What you are really seeing is light reflected from the fish!

LightLightLight Is a transverse , electromagnetic wave that

can be seen by human beings. Energy generated by sun, electric light ,fire

travels as a radiation from source and can be detected by human eyes.

Two forms of light are:

1- Incandescence light: 2- Luminescence light:

Incandescence lightIncandescence light

The emission of light from hot matter is incandescence light.

Luminescence lightLuminescence light

The emission of light ,when excited electrons fall from higher energy level to low energy level.

A luminous object is one that produces light.

An illuminated object is one that reflects light.

Luminous Object Illuminated Object

Luminous and Luminous and Illuminated ObjectsIlluminated Objects

Nature Of LightNature Of LightLight rays travel in the transparent medium present in the form of particles

When travel through vacuum present in the form of wave

Materials can be transparent, translucent, or opaque.

Each type of material affects the behavior of light in different ways

Nature Of LightNature Of Light

Transparent MaterialsTransparent Materials

A material through which you can see clearly.

A transparent material transmits light, which means it allows most of the light that strikes it to pass through it.

Some examples: windows and fresh water.

Translucent Translucent MaterialsMaterials

A material that you can see through, but the objects you see through it do not look clear or distinct.

A translucent material scatters light.Example: Jell, Soap

Opaque MaterialsOpaque MaterialsA material that either absorbs or reflects all of the light that strikes it. (It blocks light from passing through it.)

Most materials are opaque.Examples: Trees, concrete, metals

Interactions of LightInteractions of LightWhen light strikes a new medium, the light can be reflected, absorbed, or transmitted.

When light is transmitted, it can be refracted, polarized, or scattered.

ReflectionReflectionWhen you look in a mirror, you

see a clear image of yourself.

An image is a copy of an object formed by reflected waves of light.

There are two types of reflection : regular and diffuse.

Regular ReflectionRegular ReflectionThis occurs when parallel light

waves strike a surface and are all reflected in the same direction.

Regular reflection happens when light hits a smooth, polished surface.-Mirrors and still bodies of water

Diffuse ReflectionDiffuse ReflectionThis occurs when parallel light

waves strike a rough, uneven surface, and reflect in many different directions.

When this happens, you can see either a blurred reflected image or no image at all.-Rough water, paper.

Law of Reflection:Law of Reflection:

Angle of incidence = angle of reflection

Transmitting LightTransmitting Light

If light is not reflected, three things can happen as light passes through an object:

-Refraction, Polarization, Scattering

Refraction= BendingRefraction= BendingRefraction occurs when waves bend when it passes at an angle from one medium into another.

This can also happen to light!

This is seen when you place objects under water.

PolarizationPolarizationPolarization occurs when light waves

vibrate in only one plane.Light is normally “un-polarized,”

meaning it vibrates in all directions.Polarizing filters transmit light waves,

but they block all of the light that isn’t vibrating in the direction it allows through it.

PolarizationPolarizationThis technology is now used in 3-D

movies!3-D movies are produced in a way that

makes it so the image that is projected on the screen is really two images (one for your right eye, and the other for your left eye).

This is why, if you take your 3-D glasses off, you will see a blurry picture.

ScatteringScatteringScattering means that light is redirected as it passes through a medium.

The earth’s atmosphere contains many molecules. When light from the sun hits these particles, they scatter the light.

Scattering reddens the sun at sunset and sunrise.

Nature Of LightNature Of LightThe following theories explains the nature of

light THE CORPUSCULAR THEORY created in seventeen century By sir Isaac Newton States that light emitted by luminous object

consist of tiny particles of matter called corpuscles

Nature Of LightNature Of Light

WAVE THEORYCreated in seventeen centuryBy sir Christian Hygiene states that light is emitted in series of

waves that spreads out from a light source in all

direction

ELECTROMAGNETIC THEORYCreated in nineteen centuryBy James MaxwellStates that light posses both electric and

magnetic properties and can travels through a vacuum

Light wave is a part of EMR and make up EMS

Nature Of LightNature Of Light

Nature Of LightNature Of Light

QUANTUM THEORYCreated in nineteen centuryBy Max PlanckStates that light waves travels as a

separate packets of energy called “quanta” or “photons”.

correct and accurate theory