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A paper disc of radius R from which a ho...

A paper disc of radius `R` from which a hole of radius `r` is cut out is floating in a liquid of the surface tension `S`. The force on the disc due to the surface tension is

A

`T.3piR`

B

`T.2pi(R+r)`

C

`T.4pi(R+r)`

D

`T.2pi(R-r)`

Text Solution

Verified by Experts

The correct Answer is:
B
Effective length `=2pir+2piR`
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