What is light for all

 Dual nature of Light  

(a) Particle   (b) Wave

Light has dual nature particle (photon) as well as wave.

 

What is Photon. Photon is define as, very very tiny (smallest) particle/packet of energy. The rest mass of photon is zero.
 

What is wave. Wave is define as, A wave can be described as a disturbance that travels through a medium from one location to another location.
 

 

Albert Einstein's photoelectric effect experiment proves that light can behave as a particle while 

 

Thomas Young's double-slit experiment shows that it also behaves as a wave.
 

Albert Einstein proved that in 1905, light could behave as a particle by showing that a beam of light could eject electrons from metal when a suitable radiation (invisible ray) fall on metal, This suggested that light consisted of photons that could eject electrons of similar frequency. Einstein's discovery altered the prevalent theory at the time, which held that light was only a wave.
 

And light has the wave nature also, it has proved earlier by Young in 1801. In his experiment, Young shone light between two parallel slits, causing the light waves to interfere with each other and form a patter of dark and light bands. If light was primarily a particle, it would have formed two parallel lines.
 

Quantum mechanics explains the duality of light by describing it as a wave-packet. A wave-packet refers to waves that may interact either as spatially localized, acting as particle, or interacting like waves. This means light photons can either act as a particle or wave, depending on the circumstances.

 

Making wave by rope

Making wave by water

Wave example

Electromagnetic wave

Electromagnetic wave

Wave details

Wave example

Electromagnetic wave

Electromagnetic wave

Visible light definition and energy

The Light energy

 

We can not see the energy by our naked eyes except one type of energy known as sun light,  this is the only type of energy which is visible for human eyes. But other animals can see hidden part of lights.

 

The beam of light, actually it is mix up of different colors, that why every colors has different wavelength to other. Some has longest wavelength some has shortest wavelength.

 

Sun is the biggest source of light energy. While is millions of mile far from us, it emits huge amount of light energy.

 

The fastest things on this earth is speed of light, which travels 300000 km/s in air.  This is faster than the speed of anything else! But speed of light is not same every where, it began to change during change of mediums. The speed fasted speed of light are, vacuum> air> water> glass> and so on.

 

All things ( all living things, human, animals, fishes, trees, rivers, mountains, etc) which are surviving on this planet cant be survive without sun light.

 

Trees absorb light energy from sun, convert it into making  their food, Humans and animals would be unable to see anything without light energy.

  Other source of light are street bulb or home bulb and fire, torch.

 

Animals in field with sunlight

Flowers with sunlight

Illuminated bulb

Light dark combination

Leaf making food under sunlight

Tiger under sunlight

Sun radiation facts

 

The Sun Lights

 

The actual color of sun's light is white. When astronauts see the sun from space its look white.

Why its looks like white, because its light is not scattered by atmosphere.

And white color is mixture of seven colors called VIBGYOR.

But we can not see all color by our naked eyes, to watch VIBGYOR we will have to pass the sun's light through Prism or water's drops.

But there are some animals who can see all color of VIBGYOR as well as ultraviolet lights also with their naked eyes. e.g, honey bees can see ultraviolet lights, Pit viper can see infrared, Puppies, meanwhile can see into our heart, frogs can detect very sensitive photons.

Why leafs looks green, because leafs reflects only green color from VIBGYOR, and absorbed left all colors.

 

Pit viper snake

When light passing through a prism

Honey bee can also see U.V radiation

Rainbow

This frog can see U.V light

When sunlight passing through the prism

Water bubble with rainbow color

Physics lessons online for student

Lets know about Light.

Study of light is called optic.

Light travels in straight path

Light has electromagnetic energy.

Generally there are two type of light, (a) Visible light (b) Invisible light.

When we talk about visible light is known as light or optic. e.g, Sun light.

When we talk about invisible light is called electromagnetic radiation,  e.g, ultraviolet radiation

Light is made by very tiny packets called photon.

Every photons contain lots of energy.

Speed of light changes with change of mediums (objects or materials).

 

Light

Light and its components

When light passing through the prism

Lets know about Shadows.

99.99% Space is dark (full of shadows).

Because there is no sufficient light, light is visible when it has an object in its path.

No one has seen the shadow of moon, sun, Jupiter, mars, earth, Venus etc in space.

There is no shadow of astronauts has found in moon.

In ancient time people was thinking about shadow formed by sun, thought lot and utilized this principle in making the world’s most primitive clocks, the sundials.

 

Light and shadow combination

shadow and light combination

Earth from space