Question

A metal ball $1.6 \mathrm {~g} \mathrm {~cm} ^ { - 3 }$ If both the balls have the same diameter and attain the same terminal velocity, the ratio of viscosity of water to that of the liquid is

• A. 2.0
• B. 0.5
• C. 4.0
• D. Indeterminate due to insufficient data

Answer 1

Answer: (B)

0.5

Answer 2

The terminal velocity of the body of radius r, density $\rho$ falling through a medium of density $\sigma$ is given by

Where $\eta$ is the coefficient of viscosity of the medium

… (1)

And ….. (2)

Where the subscripts and represent metal ball and metal ball respectively.

and (Given)

Substituting the given values, we get

Substituting the given values we get

($\mathrm { cm } ^ { - 3 }$)

$= \frac { 2.2 } { 4.4 } = 0.5$