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.

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THE EARTH, A SUPER ORGANISM

JOIN MY COURSE: "Become a programmer in a day with python" A man called 'love lock' (what a name) proposed a theory called Gaia theory, named after Greek Goddess. It says, "Earth is a self-regulating organism like a human being. The organic life in it interacts with in-organic matter and maintains atmosphere, temperature and environment". Hence the earth is still suitable for the life to thrive. Imagine, in a particular place, there are lot of flowers. Some flowers are white and some are darkly coloured. We know, white reflects light and heat while dark absorbs the same. White flowers can thrive in hot climate. But dark flowers requires cold climate. The absorption and reflection balances and the environment reaches average, warm temperature at which both the flowers can co-exist. This is the essence of "Gaia" theory. On our earth, the oxygen constitute 20% of the atmosphere. The oxygen level is always mai

THE PARABOLA

A jet of water shooting from a hose pipe will follow a parabolic path. What is the so special about parabola. Y= x^2 Draw a graph for the above equation. It will result in a parabola. This parabola is also called unit parabola. Any equation involving square will yield a parabola. Example: Y = 2x^2 +3x+3 (also called quadratic equation) X= 2 and -2, both satisfies the equation 4 = X^2. Parabolic equations always have two solutions. Any motion taking place freely under gravity follows parabolic path. Examples: An object dropped from a moving train, A bomb dropped from flying plane, A ball kicked upwards. If a beam of light rays fall on the parabolic shaped mirror, they will be reflected and brought to focus on a point. This fact is made use of in Dish Antenna, Telescope mirrors, etc. Inverted parabola shape is used in the construction of buildings and bridges. Because the shape is able to bear more weight. A plane

DISORDER IS THE "ORDER OF THE DAY"

Imagine a balloon full of air. The air molecules are moving randomly inside the balloon. Let us pierce the balloon with a pin. The air rushes out. Why should not the air molecules stay inside the balloon safely and ignore the little hole? That is not the way the world works. The molecules always "want to occupy as many states as possible". Hence the air goes out in the open to occupy more volume. The things always goes into disorder (entropy) and the disorder increases with time. The above statement is what we call "second law of thermodynamics". Consider a cup of coffee on the table. Suppose the heat from entire room flows to your cup of coffee, the coffee will boil and the rest of the room will freeze. Freezing means bringing things to order and arrangement. It violates the second law. Hence it will never happen. Hence heat must flow from high temperature to low temperature and not the other way. The air molecules in y

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