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why rainbow always in semi circular shape? why it is not in circle or rectangular shpe.

hello dear,
Rainbows always appear round because
they are formed at a constant angle around
the anti solar point (the shadow of your head).
The shape of something described by an arc a
constant distance away from a point is a circle,
which is called round...............

<GOOD QUESTION>

Well it is because the density of the environment and we see the rainbow it look always bended but it is actually not , well you can better understand it from optics and prism section of the physics of higher class.
Go and look if not find then i will give you the full detail after some day.
thanks
bye
again good .....very good

http://wiki.answers.com/Q/Why_does_a_rainbow_appear_bent_or_arched_in_a_semi circle_in_the_sky

why is rainbow always semi circular

First of Rainbow is not Semi circular in Shape. It is Circular or Oblate Spheroid in shape.

We, Con not able to see the full Circular Rainbow only because it make 42 Degrees arc over our Head, which unables us to capture the whole Circular part, which requires 84 Degree of Eye view. Which is impossible as because general Rainbow form at an angle of 42 dergees.

But in some rare cases, we are able to see the Full Circular shaped Rainbow.

As for example- If a Rainbow is seen from a considerable height say when some one is travelling in Airoplane.

Scientist have also Pictured Full Circlar Rainbow in "Malasia" Have a look on it.



Hope now you doubt is clear to some extent.

GOOD QUESTION.

Regards
~Faiyaz~

rainbow is circular in shape it is never semi circular
we see it so because our earth is round and the rainbow is formed at such an angle with our eyes that we cant see the complete rainbow.
thats y it appears semicircular
you can refer the physics parti 2 of ncert for 12th std for complete details

dear friend,
first of all these type of question are not meant to be asked in entrance exam forum.so better avoid asking such type of question.moreover for your kind information rainbow is never semi circular in shape.it is circular but it appears to be in semi circular.which is due to the distance and our inability to bend more than it is supposed to be.

That is famous theory from optics.
As, said by other members,this happens on the principle of lessing surface tension.

still dont understand : (

this is because of surface tension property.
take the example from ncert clss 9.

Hi,
Rainbows always appear round because
they are formed at a constant angle around
the anti solar point (the shadow of your head).
The shape of something described by an arc a
constant distance away from a point is a circle,
which is called round...............

Thanks

Hi, u can read the fell explaination from the site given below
www.en.wikipedia.org/wiki/Rainbow

best wishes

Dear,
According to me -
Well it is because the density of the environment and we see the rainbow it look always bended but it is actually not , well you can better understand it from optics and prism section of the physics of higher class.
Go and look if not find then i will give you the full detail after some day.
Thanks.
All the best.

FIRST OF ALL I WANT TO TELL YOU ABT RAINBOW FORMATION. AS YOU HAVE OBSERVED IT ONLY FORMED AFTER RAINING BECAUSE SUM DROPLETS IN AIR REMAINED AFTER RAINING WHC ACT AS PRISM AND WHEN LIGHT RAYS FROM SUN PASS THROUGH IT , IT DISPERSE INTO SEVEN COLOURS KNOWN AS RAINBOW. ACTUALLY RAINBOW IS A COMPLETE CIRCLE BUT IS OFTEN VIEWED AS CIRCULAR ARC IN SKY.
Observers on the ground only view the top half of the circle since the bottom half of the circular arc is prevented by the presence of the ground (and the rather obvious fact that suspended water droplets aren't present below ground). Those who are fortunate enough to have seen a rainbow from an airplane in the sky may know that a rainbow can actually be a complete circle. Yet observers in an airborne plane can often look both upward and downward to view the complete circular bow.

The circle (or half-circle) results because there are a collection of suspended droplets in the atmosphere that are capable concentrating the dispersed light at angles of deviation of 40-42 degrees relative to the original path of light from the sun. These droplets actually form a circular arc, with each droplet within the arc dispersing light and reflecting it back towards the observer.

Thats a good question.

The reason behind this is that as we know that light travels from sky with multiple reflection it goes on reflection with different angles and thus for semi circular in shape.

The RainBow which we usually watch in the Sky is in Semi Circular in shape But they actually is in Circular in shape.

In rare cases They appears to be Full Circular But usually Semi Circular.

& this is because the angle at which the light ray incident on the drop gives a semi circular shape to the rainbow

The reason why the rainbow is curved is because all the angles in the water drop have to be just right for the drop to send some sunlight to viewer
only those water droplets that have the same angle formed by viewer, the drop, and the sun will contribute to the rainbow.

Reason of different shapes of Rainbow

You can see curve, semicircular and less than semicircular shapes of a rainbow,because all the angles in the water drop have to be just right for the drop to send some sunlight to you, standing on the ground. So, with the sun *behind* you, only those water droplets that have the same angle formed by you, the drop, and the sun (this angle happens to be approximately 42 degrees) will contribute to the rainbow. Other droplets send their light somewhere else, and if you move to a different location, new droplets are needed to make the rainbow you see in the new location. This is why you can't go to the end of a rainbow to find the mythical leprechauns and pots of gold; anywhere you stand, the rainbow is formed by faraway drops of water reflecting and bending sunlight. The rainbow is curved because the set of all the raindrops that have the right angle between you, the drop, and the sun lie on a cone pointing at the sun with you at one tip. The rainbow may look semicircular if the sun is setting or rising (a good time to see a rainbow because the sunlight at that time can get under rain clouds because it is traveling horizontally). If the sun is higher in the sky, the earth gets in the way and you may see less than a semicircular rainbow.

Well actually, a rainbow is a full circle we can see only half circle because of horizon, to understand why it is circular shape one would know few things about rainbow.

please visit:

optics.kulgun.net/rainbow


all the best......................

Hi,
according to my knowledge-
The RainBow which we usually watch in the Sky is in Semi Circular in shape But they actually is in Circular in shape.

In rare cases They appears to be Full Circular But usually Semi Circular.

& this is because the angle at which the light ray incident on the drop gives a semi circular shape to the rainbow


Thank

ALAKH: Sir ,why do we feel jerking to touching tha open current wire with earthing ? if we touch the open current wire without earthing then what shall we feel?why cant we touch to transmisstion line without earthing? plz explain me in deep, sir

Dear friend,

See dear as the earth is round or circle in shape that is why the rainbow must be always in circular shape but the rainbow is semi circle because of surface tension property.
It will be much more clear when you will go to a see or ocean there you will see that after a some kilometer the see or the ocean meet to the sky.By this way it is clear that the earth is round in shape.

than you.

its because of total internal reflection

A rainbow is produced when sunlight refracts while entering water droplets hanging in
the air, a total internal reflection at their back surface and a second refraction while
coming out of the droplets. Most of the light of the rainbow emerges close to

the “angle of minimum deviation”. This angle is 42 degrees with respect to the
direction of the incidence of sunlight. Therefore, we will see a rainbow at this
angle with respect to a line connecting the Sun with the back of our head.

This can be true only for a circular arc at an angle of 42 degrees. This circle
intersects the Earth and standing on the Earth, the largest sized arc we can see
is a semicircle; this occurs when the Sun is close to the horizon.

Originally Posted by Unregistered

why is rainbow always semi circular

rainbow is circular in shape it is never semi circular
we see it so because our earth is round and the rainbow is formed at such an angle with our eyes that we cant see the complete rainbow.

Rainbow is actually circular in shape.A rainbow is curved or semi circular due to angle requirements.

We never see the entire rainbow because of the horizon.

A rainbow is made by rays of light from the sun which are bent and reflected by raindrops so that they come back to our eyes.

The formation of a rainbow involves a series of physical phenomena - reflection, refraction, dispersion and total internal reflection.
The occurence of each of these is due to the interaction of light with air and water and the boundaries between them.

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