THE DISCOVERY THAT BOUGHT EINSTEIN THE NOBLE PRIZE

We use remote control that triggers TV, AC, etc,. How it works? How the eye's vision is communicated to the brain?
How a bar code reader in a mall works? How the smartphone camera shoots a picture?

"When light waves, infra red rays, ultraviolet falls on certain chemicals like zinc, electrons are ejected out and electric current starts flowing". This process is known as photoelectric effect. It is instantaneous. How can the waves push electron? Can sound waves push an object? No. Can stream of fire disturb a concrete wall? No. So there must be 'something' in the photoelectric effect.

Einstein investigated and proved that light waves sometimes behave like pockets of energy or particles called photons. When one photon strike an atom in a material, one electron is ejected out instantly. It is like throwing a heavy stone on the wall and forcing out one brick. For this discovery he was awarded noble prize.

Now we understand that waves behave like particles. Later people argued, the atomic particles must also behave like waves due to symmetry. So a new science was born.

Photoelectric effect has many natural and artificial applications.

Light image falls on the retina of the eyes and triggers photoelectric effect. The generated current is sent to the brain through nerves and the brain process it. Then we perceive the image and the object.

When the sunlight falls on the plant leaves, the ejected electrons starts the photosynthesis process which is an essential process for the life to sustain on this planet.

When a burglar somehow enters the 'strong room' of a bank, this photoelectric effect starts an alarm. Automatic street lights also works based on this principle.

Long back movie became talkie because of this principle. Voice was converted into electric current then into light and recorded on one side of the film (sound track) . In reproduction the photoelectric effect was used to convert the light into current and then to voice.(today cinema is digitized). So we have so many interesting uses for photoelectric effect.

This effect connects light and electricity; waves and particles; photons and electrons.

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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 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. ...

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 ...

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