Question

A metal plate of ${10}^{3}c{m}^2$ rests on a layer of oil 6 mm thick.A tangential force ${10}^{-2}$ N is applied on it is on it to move it with a constant velocity of 6 $cm{s}^{-1}.$ What is the coefficient of viscosity of the liquid?

• A. 0.1 poise
• B. 0.2 poise
• C. 0.3 poise
• D. 0.4 poise

Answer 1

The correct option is A 0.1 poise

$\text{We know that}$

$\eta =\frac{fdl}{Adv}$

$\text{Given}f={10}^{-2}Ndv=6cm{s}^{-1}$

$dl=6mm=0.6cm$

$A={10}^3{cm}^2$

$\text{so}$

$n=\frac{{10}^{-2}\times 0.6}{{10}^3\times 6}$

$=0.1\times {10}^{-5}$

$=0.1\text{poise}$

$\text{Answer:}\text{(A)}$