Why the shape of rainbow is semi-circle, why it is not square, traingle,e.t.c?

Answer 1

RAINBOW

Rainbows are formed by light reflecting from rain drops. Often we see only one rainbow, called the primary bow, but sometimes we can see a second, outer rainbow, called the secondary bow.



Primary Bow
When sunlight strikes a raindrop, some of the light is refracted at the first surface, internally reflected from the back surface, and refracted again on exiting the rain drop.



For each colour there is a maximum angle of deviation of the light. So, in rain drops there is a minimum angle, for each colour, between the incident and exit rays. For red, this is 42° and for violet it is 40°. The nature of internal reflection is such that many rays will emerge near this minimum angle.

Hence the sunlight will appear to be concentrated over a small region of the sky in a narrow range of angles from 40° to 42° and separated into colours, from blue to red.

Secondary Bow
Some of the sunlight is also refracted at the first surface, but is reflected twice internally from the back surface, and refracted again on exiting the rain drop.



Again there is the same maximum angle of deviation for each colour, but now the double internal reflection leads to a minimum angle between the incident and exit rays of 50.5° for red and 54° for violet. The bow is at a higher angle, and so will appear higher in the sky. And the colours are reversed, going from red to blue.

The amount of rainbow you see depends on the angles between you, the sun, and the raindrops. As the sun rises, less and less of the rainbow is visible. As you climb a mountain, you see more and more of the rainbow.

Answer 2

Rainbows are around because of the fact the easy is being meditated from interior a droplet of water that's sorta' around. If I remember wisely the perspective is 40-40 two tiers. now and lower back there's a 2d, third or 4th mirrored image from the droplets which will produce a double, triple or quadruple rainbow. in some situations you will discover an inverted rainbow (the arc is going up) and the purple arc would be on the interior relatively than on the exterior as in a rainbow that arcs down. Rainbows seen in a valley from a mountain or rainbows stated from an airplane could be complete circles. a individual status beside you will see a distinctive rainbow than you and somebody status some ft away won't be waiting to verify the rainbow. Rainbows are greater usually seen and greater bright close to dawn and sundown. because of the fact the sunlight gets larger interior the sky the easy meditated from the drops is exterior our viewing perspective. now and lower back you will discover the mirrored image of a rainbow in a lake and you could no longer see the rainbow because you're on the incorrect viewing perspective.

Answer 3

It has nothing to do with the sun being round, or the earth being round. Each rain drop reflects the sun at a fixed angle which depends on the refractive index of water. All the rain drops have the same refractive index. Therefore the angle through which the sun's light is reflected is the same for every ray of light coming back to you. So the edge of the rainbow will appear to be same distance from the centre all the way round, which means it is a circle.

Answer 4

Light passing through a prism(in this case caused by moisture in the air) is converted into an arc of 7 colors detectable by the naked eye and several others that are not. If not for the earth getting in the way it would be a full circle and not just an arc.

Answer 5

I will not answer the question, beause as you have thought it out you ourself can solve it. But I will give you a hint.
The rainbow appears as a semicircle only when you stand on the earth surface but as you go high up in the sky, it appears as a full circle!
Another hint, the water particles on which diffraction of sunray takes place are spherical in shape.
Have you found the correlation?

Answer 6

well according to me light reflected by the rain drops left on the cloud causes rainbow. as the drop has a curved surface it reflects a curved reflection of light. And hence the shape of rainbow is approximately semi circular!!
AM I RIGHT????

Answer 7

actually we only see half of a rainbow's arc. try facing your back to the sun and hold a water hose in front of you. set the nozzle to fine and spray away. you'll see that the rainbow forms a full circle.

this is because the rays of the sun is refracted in a circular pattern (since the sun itself is circular) and is broken down to its spectrum in the same fashion.

when we see a rainbow after a downpour, or during a fine drizzle, we see a bigger refraction of the sun's light from a farther distance, showing only half, or sometimes even one quarter of the whole spectrum.

Answer 8

when i was on a plane once i noticed there was a rainbow below in a full circle maybe it has got something to do with the planet being a sphere?

Answer 9

because when light is refracted due to raindrops, we could only see some part of it as earth is a big & round in shape.so as we go up in sky we could see more of and more part of rainbow.

Answer 10

Because the earth is round.