Lens

Seems nobody interested to answer, fine, am only answering it then.

When the lens is bisected horizontally along the principal axis, the horizontal cut doesn't change the shape of the surfaces, it only makes the lens smaller, so the focal length stays the same,i.e, f only.

But when it is bisected along the vertical line, there is the change in the shape of the lens, the radius of curvature becomes half of the original value, i.e, R/2 , so the focal length becomes double,i.e, 2f

Same thing happens with the concave lens too

[1]

when convex lens is bisected horizontally focal length remains same because there is no change in the thickness of the medium of the lens,hence the rays of light are refracted similarly as before , there is only change in the size of lens but u should remember that every part of the lens forms complete image of the object. so there is only change in the brightness of the image.

but when it is bisected vertically f_net becomes 2f because

1f_net=(u -1) [1R₁ - 1R₂]

put R₁ = R AND R₂= -R

F_NET = R/2(U-1)

BUT IF BISECTED VERTICALLY PUT R₁ = R AND R₂=∞

SO F '_NET= R/(U-1)

F'_NET= 2F_NET

SIMILARLY U CAN DO FOR CONCAVE LENS.....

TYPO WAS TOO MUCH LONG....

Thanks Nihal [1]

IF IN THE ABOVE CONVEX LENS , AFTER BISECTING THE LENS HORIZONTALLY THEY ARE PUTTEN ABOVE PRINCIPAL AXIS TOUCHING EACH OTHER HAVING POINTED ENDS OF BOTH UPWARD AND FLAT END TOUCHING PRINCIPAL AXIS...

WT IS THE NET FOCAL LENGH OF THE SYSTEM?

Answer is f/2 because the radius of curvature becomes double now

the radius of curvature becomes double now???

EXPLAIN ME U COULD BE CORRECT.....

IF IT WAS BISECTED VERTICALLY AND PUTTEN IN SUCH A WAY ONE AFTER THE OTHER AND FLAT ENDS IN THE SAME DIRECTION BUT NOT TOUCHING EACH OTHER..

WT NET FOCAL LENGTH OF THE SYSTEM???

IF IN THE ABOVE CONVEX LENS , AFTER BISECTING THE LENS HORIZONTALLY THEY ARE PUTTEN ABOVE PRINCIPAL AXIS TOUCHING EACH OTHER HAVING POINTED ENDS OF BOTH UPWARD AND FLAT END TOUCHING PRINCIPAL AXIS...

WT IS THE NET FOCAL LENGH OF THE SYSTEM?

I dont have a solution like your's but I just applied my logic in saying that the focal length becomes f/2.

See when we keep the convex lens in contact with each other, aren't we increasing the size

of the mirror and hence the radius of curvature. Since two convex lens of radius of curvature

R are joint perfectly to each other with their flat side in the same direction, the radius of

curvature of the resulting lens becomes twice,i.e,2R.

So by using the kiddo formula f = R/2, I said that focal length becomes f/2.

for the first question that i asked ur answer is correctthere is a proper method

for my second question i think that u mistook the question try it carefully to get its correct geometry....ofcourse not similar to ur question

tell me how to add smileys..okkk

[1] [12] [5] [3] [4]thanx

am not able to get the geometry of your 2nd question, help me out in that.

for the first question that i asked ur answer is correctthere is a proper method

All methods are proper which give the correct answer. Jab answer easily mil jata hai, toh

complex equation use karne ki kya jaroorat [3][3][50]

which board mein?

Anyways post the answer or give some hints for that question