Banner 0
Banner 1
Banner 2
Banner 3
Banner 4
Banner 5
Banner 6

Q.

A thin metal disc of radius ‘r’ floats on water surface 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

see full answer

Talk to JEE/NEET 2025 Toppers - Learn What Actually Works!

Real Strategies. Real People. Real Success Stories - Just 1 call away
An Intiative by Sri Chaitanya

a

2πrT+W

b

W-2πrT cosθ

c

2πrT cosθ+W

d

2πrT cosθ-W

answer is A.

(Unlock A.I Detailed Solution for FREE)

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Detailed Solution

solution

As depicted, the disc is being acted upon by three forces:
weight mg of the metal disc upward at an angle with the vertical buoyancy force, and downward force caused by surface tension (T)
Equating all forces are equal,

mg=2πrTcosθ+W

Hence the correct answer is 2πrTcosθ+W

Watch 3-min video & get full concept clarity

Best Courses for You

JEE

JEE

NEET

NEET

Foundation JEE

Foundation JEE

Foundation NEET

Foundation NEET

CBSE

CBSE

score_test_img

Get Expert Academic Guidance – Connect with a Counselor Today!

whats app icon