Question

The tangential forces per unit area of the liquid layer required to maintain unit velocity gradient is known as:

• A. coefficient of gravitation of liquid layer
• B. coefficient of friction between layers
• C. coefficient of viscosity of the liquid
• D. temperature coefficient of viscosity

Answer 1

Answer: (C)

coefficient of viscosity of the liquid

By definition of Tangential force which is equal to the product of coefficient of viscosity, velocity gradient and area.
i.e $F_T=\eta A\frac{dV}{dX}$
So, $\frac{F_T}{A}=\eta \left(1\right)$
Therefore, the tangential force per unit area of the liquid layer required to maintain unit velocity gradient is known as Coefficient of viscosity of the liquid.