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Q46.
Ans: C.
I m getting D.

Q46.  A thin metal disc of radius r floats on water surface and bends the surface downwards along the perimeter making an angle θ with vertical edge of the disc. If the disc displaces a weight of water W and surface tension of water is T, then the weight of metal disc is
(A) 2πгT + W
(B) 2πrТсosθ – w
(C) 2πrТcosθ +W
(D) W – 2πrTсosθ

Dear Student

T h e space w e i g h t space o f space m e t a l space d i s c equals t o t a l space u p w a r d space f o r c e equals u p t h r u s t space f o r c e plus f o r c e space d u e space t o space s u r f a c e space t e n s i o n space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space equals w e i g h t space o f space t h e space d i s p l a c e d space w a t e r plus T cos theta left parenthesis 2 pi r right parenthesis space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space equals space W plus 2 pi r T cos theta
Therefore, the answer is option (C)

Regards

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