JEE Advanced 2020 Full Test 3 Paper 1

Let R be the radius of the circular layer of water.
Then, πR2d×ρ=m ......(1)
Pressure at A=p0−‌

2T

d

......(2)
Thus pressure between the plates is less than the atmospheric pressure and so the plates are pressed together as though attracted towards each other.
F, force of attraction =∆p× area ⇒F=‌

2T

d

×πR2
⇒F=‌

2T

d

×‌

m

d⋅ρ

=‌

2Tm

d2⋅ρ

=‌

2×0.4×10−3×0.08

0.012×10−4×1000

=6.4N