LET THERE BE LIGHT

    

Light and eyes gives us 70% of our knowledge.  Hence we should have some knowledge of light.

     Sun's rays, LED glow, candle flame, festival sparklers.  What is light?  How it is created ?  Let us explore.  

     We know electrons are circling in the atom.  Electron absorbs some energy and goes to high speed orbit.  Analogy:  Let us raise a stone from the ground to a certain height.  

     The electron fall back to the low speed stable orbit.  While it moves to lower orbit,  it follows slightly spiral path and its speed decreases.  Consequently the electric field associated with it{electron being a electric charge} changes and creates changing magnetic field perpendicular to it.  In a nut shell; when the electron jumps from higher energy level to lower energy, an electromagnetic disturbance is created.  Let us drop the stone in a water body.  It creates a mechanical disturbance in the water.

     The electromagnetic disturbance comes out from the atoms as a electromagnetic wave.  It can travel by itself in an empty space.  The disturbance in the water creates water wave and spreads on the surface. 

     If the wavelength of EM waves falls in the visible region { 400 to 800 nanometer}, we say light is emitted from the atoms.

     So the light is electromagnetic waves born from atoms.  Lights wavelength is very small because it originates from atoms.

    For sodium atoms the wave length falls in yellow light region.  Neon emits blue lights.  Organ, the red.  Mercury emits all the colours which mixes up and appears as white. Light spectrum emitted from an element's atom is unique and it is like a signature of the atom.

     No artificial light can match the sunlight.   The sun light not only illuminates the world but gives us courage and strength.