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Monday, 16 October 2017


           WHAT IS LIGHT?

We all are familiar with Light. Without light we can not imagine of our world. Imagine a World in the dark, a world where nothing exists except Light. Horrible! Right? We receive light in various form such as in the form of sunlight, from electric bulb, and more other forms. Now coming to the topic- what is Light?
Since our childhood, we had been taught by our teachers that Light is the form of energy.


Light, as we know, is the form of energy. It is the smallest quantity of energy that can be transported or that can travel in the form of Photon. Now the question arises, what is Photon? Photon is the type of particle (or we can say elementary particle) which represents a quantum of light or other electromagnetic radiation. Photon carries energy proportional to the radiation frequency but has 'zero' rest mass. The concept of rest mass derives from the special theory of relativity. The rest mass is the mass of the particle which is measured by an observer who sees the particle with zero speed. Photon can be formed or destroyed, but without real mass. Like, if we talk about Photons, they are simply energy carriers and can be created and destroyed. If we shine light on a surface, the electrons of the atom on which light is incident, absorb the light and jump to an excited state and destroys the Photons. On the other hand, Photons is created instantaneously out of the vacuum. The high energy level electron instantly get converted into a lower energy electron or Photons. Photons cant be splitted. Light actually means a 'visible light' which is a part of an electromagnetic spectrum. Visible light is generally a tiny part of an electromagnetic spectrum and energy in the form electromagnetic radiation. This spectrum consists of enormous range of wavelength and frequencies. In these range, gamma rays have the smallest wavelength because it is highest energy (or excited) photons. Most of these radiations have wavelength of about 10 pm (which is 0.000000000001m or one trillionth of a meter), which is way smaller than the size of Hydrogen atom. The visible light which we can observe lies in the middle of the spectrum and has wavelength of 700 nm to 100 nm, which is equal to the size of bacteria. On the other hand of spectrum, low frequency radio wave can have wavelength of 100 km, which is equal to the radius of the asteroid that killed Dinosaurs. The biggest wavelength which humanity discovered till date is of 1000 km (which is the radius of Sinus B, a white dwarf) to 100,000 km (which is bigger than the Earth's diameter). In spite of having variations of wavelength, these waves have the same wave speed and they all travel at a speed of Light but at different frequencies. Now the question arises, Where does Light comes from?


In the simple day to day life, if anyone asks that where does Light comes from? We will start questioning about that person's brain. However, we will them that Light comes by lighting out fire, by sun, by switching on the bulb and from many other sources. These will be the answers what we experience in our daily life. But... Are we 100% true? The answer is "NO". We are not even close to the correct answer. Leaving all these normal life experiences, and coming to basic to find the answer that WHERE DOES LIGHT COMES FROM?
They are created or formed when the atoms or molecules drop from their high energy state to lower state of energy. When they drop from their high energy state to lower state of energy, they loose energy and emit it in the form of radiation.
Picture on the left side shows dropping in the energy state of an electron at microscopic level.
Now the another question arise here, WHAT IS THE FASTEST SPEED FOR WAVE TO TRAVEL IN THE SPACE?


We all know that the speed of Light is the ultimate speed, i.e 300,000 km/second and nothing can travel faster than the speed of Light. Obviously, the maximum speed that an electromagnetic wave can attains is the speed of Light. Light can travel at a speed of 1 billion km/hour! Any particles that has 'no' mass, travels at a speed of Light without acceleration (as we have seen above in the case of Photons, which have zero rest mass). Let us consider a candle, or a bulb. When we burn a candle or switch on the bulb, the Light emits up and without acceleration it attains its maximum speed 'c'. What does this means? If the speed of light attains its maximum speed without acceleration, then why 'c' is FINITE? Why 'c' is considered as a constant? Why the speed of Light can not be increased by increasing an energy? These are question which keeps on shocking my brain whenever I think about it!
That's all for now!..
Hope you enjoyed it.. Be updated for the curiosity!
Good Bye.. Cheers!!..

About Author


A tech and gadget lover who is passionate about writing. Life Goals: To shout from the Mountain Peak: Yes, I did it.


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