question_answer

            If a ball of steel (density\[p=7.8\text{ }gc{{m}^{-3}}\]) attains a terminal velocity of \[10cm\,{{s}^{-1}}\]when falling in a water (Coefficient of Viscosity \[{{\eta }_{water}}=8.5\times {{10}^{-4}}Pa.s\]) then its terminal velocity in glycerine \[(p=1.2gc{{m}^{-3}},\eta =13.2Pa.s.)\] would be, nearly:                                               [AIEEE 11-05-2011]

A) \[6.25\times {{10}^{-4}}cm\,{{s}^{-1}}\]

B)      \[6.45\times {{10}^{-4}}cm\,{{s}^{-1}}\]

C) \[1.5\times {{10}^{-5}}cm\,{{s}^{-1}}\]

D)      \[1.6\times {{10}^{-5}}cm\,{{s}^{-1}}\]

Correct Answer: A

Solution :

[a]