WHY NO BLACK FLOWER?

An artist may say 'black is a colour'. But physicist says, 'black is just a absence of light. A green leaf absorbs all the colours in the sunlight except green. When it reflect only green light, it looks green. A black shirt will absorb all the light and emits none. Hence it looks'black'. Consequently the wearer will feel warm.

Flowers normally have soft petals. Hence they have short life. Had there been a black flower, it would absorb all the solar radiation and whither quickly. The flowers normally have white or bright colours.

Solar panels, umbrella, solar cooker are black so that they can absorb the sun's heat fully.
There is star with infinite density, heavy mass and enormous gravity. It attracts and absorbs everything due to its immense gravity. Even it swallows light. Hence it is called 'black hole'.
Take black iron metal. Heat it. First it will turn yellow, then orange, red, blue, and white. So a black body is good emitter also. The 'black body' helped to discover 'photons' and gave birth to 'quantum physics'.
Ultraviolet light is called black light since it is invisible. Black light can be used to detect counterfeit bank notes. Some features in the 'bank notes' are visible only under UV light.
When two light waves meet, we think it will result in more brightness. But sometimes, the two light wave cancel each other and gives us darkness. (can be shown only in a lab).
There is also bright side to darkness. Without darkness, we can not explore sky and cosmos; we cannot sleep peacefully; we cannot enjoy a movie; we cannot study and under stand the light; we cannot take a photo-camera means dark room; we cannot enjoy laser show and so on.
All the electronic gadgets are black in colour. Other colours and white will disturb the picture that is displayed.
Black hair bordering a girl's face adds more beauty.
Without dark, brightness is a boredom.
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LISSAJOUS FIGURES

Definition: "When a particle is subjected to two sine wave motion or two oscillatory motion at right angles, the particle describes lissajous figures". We know sine wave motion and circular motion is basically same. Hence we draw two circles A and B perpendicular to each other. The circle B rotates twice faster than circle A. That is, frequency of circle B is two times than that of A. A particle at the intersection of two circles is subjected to two sine wave motion A and B at 90 degree simultaneously. The particle will describe figures depending on the frequency and phase of A and B . In our case, the ratio of frequency is 1:2 and the two waves are in phase. To draw lissajous figures : A moving point in both the circles are chosen. Here we should remember; during the time taken by the circle A to complete one rotation, circle B completes two. Hence the points are marked on the circles according to their speed. Then straight lines

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

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 'Pay out per round\. The probability for a win = p The pay-out in case of win = V No. of rounds = n The expect

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