Question

If ${\eta }_1$ and ${\eta }_2$ are the coefficients of viscosity of two liquids $d_1$ and $d_2$ their densities and $t_1$ and $t_2$ the flow times in Ostwald viscometer, then:

• A. $\frac{{\eta }_1}{{\eta }_2}=\frac{d_1{t}_2}{d_2{t}_1}$
• B. $\frac{{\eta }_1}{{\eta }_2}=\frac{d_2{t}_2}{d_1{t}_1}$
• C. $\frac{{\eta }_1}{{\eta }_2}=\frac{d_1{t}_1}{d_2{t}_2}$
• D. $\frac{{\eta }_1}{{\eta }_2}=\frac{d_2{t}_1}{d_1{t}_2}$

Answer 1

The correct option is C $\frac{{\eta }_1}{{\eta }_2}=\frac{d_1{t}_1}{d_2{t}_2}$

If ${\eta }_1$ and ${\eta }_2$ are the coefficients of viscosity of two liquids $d_1$ and $d_2$ their densities and $t_1$ and $t_1$ the flow times in Ostwald viscometer, then

$\eta \propto d$ .......(1)

$\eta \propto t$ .......(2)

$\therefore \eta =d\times t$

Thus, ${\eta }_1=d_1\times t_1$

${\eta }_2=d_2\times t_2$

$\frac{{\eta }_1}{{\eta }_2}=\frac{d_1{t}_1}{d_2{t}_2}$
In Ostwald viscometer, the time of flow of equal volumes of two liquids is compared through the same capillary.

Hence, the correct option is $\text{C}$