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QNEET-2018-Ph-895: NEET 2018 Physics - Class 11 NEET-2018-Ph-895 Solution: A small sphere of radius 'r' falls from rest in a viscous…
A small sphere of radius 'r' falls from rest in a viscous liquid. As a result heat is produced due to viscous force. The rate of production of heat when the sphere attains its terminal velocity is proportional to
Multiple Choice Options
- A r 3
- B r 2
- C r 5
- D r 4
Step-by-Step Verified Solution
Power = rate of production of heat = F.V
= 6 � _ rV T .V T = = 6 � _ rV T 2
[ As F = 6 � _ rV T from stoke�s formula ]
_ Terminal velocity V T = 2 r 2 ( _ _ _ ) g 9 _
_ V T _ r 2
_ Power _ 6 � _ r [ 4 r 4 ( _ _ _ ) 2 g 2 81 _ 2 ]
_ Power _ r 5