THE INGENIOUS DEVICE

THE INGENIOUS DEVICE - GRATING

When I say, sound waves can bend, it cannot be observed in open space. Suppose, a man speaks from the stage in a hall and you are standing outside the hall. You can still hear his speech. It proves that the sound waves bend around the doors and windows and reach you. Wavelength of sound and width of door are comparable. Hence the bending of waves or diffraction can easily be observed.

The light waves are very very small. So its bending cannot be observed through house doors. So we have to construct small slits suitable to it's wavelength.

A piece of glass is taken and using a diamond needle, so many lines (rulings) are drawn on it. Nearly 5000 lines per mm. The rulings are opaque and the space between the rulings are transparent. Hence they act as 5000 slits per mm. Now the slits are comparable to the size of light's wave. This device is called 'grating'.

If the light is passed through grating, it will bend at all the thousands of slits. All the bent light rays in a particular direction can be brought to focus using a lens. Now the diffraction of light can be easily observed and studied.

The diffraction grating is widely used in the place of prism.

Note: Arrangements of atoms in some crystals act like a natural grating.

Comments

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, ...

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 ...

CASINO'S GAME

Let us find out how the casino survives with mathematics. Say, your friend invite you for a game of dice. You must bet (wager) 2 dollars. If you roll 'six' you will get back 8 dollars. The game will go on for 30 rounds. All sounds good. The probability of rolling 'six' is 1/6. Since the game will be played for 30 times, the 'expected win' is 30*1/6 = 5. That is, you are expected to win 5 rounds out of 30. Hence your gain will be 5 * 8 =40 dollars. ok. This also implies that you will loose 25 rounds. Hence your loss will be 25*2 =50 dollars. Your net gain will be gain-less = 40-50 = -10 dollars. For 30 rounds, the loss is -10 dollars, Hence, for one round =-10/30 = -1/3 dollars. There will be a loss of -1/3 or 0.33 dollars per round. It is not a fair game. Let us make a simple formula to calculate 'Pa...

sciencecapsules

Search This Blog