Ncert Exercises & Solutions

The SI unit of viscosity coefficient $(η)$ is-

1. Pascal

2. Nsm^-2

3. km^-2s

4. Nm^-2

Hint:

f = ηA \frac{dv}{dx}

Step 1:

The SI unit of viscosity coefficient

(η)

is Nm^-2 or Nsm^-2.

As we know that,

f = ηA \frac{dv}{dx}

Where,

f = force

η = viscosity coefficient

\frac{dv}{dx} = velocity gradient

Step 2:

Substitute SI units of

f = N, dx = m, A = m^{2} and v = {ms}^{- 1}

in above equation, to get,

η = \frac{N \times m}{m^{2} \times {ms}^{- 1}} = {Nm}^{- 2} s

Hence, the SI unit of

η

is Nsm^-2