Coefficient of viscosity of a liquid is defined as the viscous force acting per unit area between two adjacent layers of a liquid with a velocity gradient normal to the direction of flow of the liquid.
The formula for Coefficient of viscosity (η) of a liquid is given as,
where F= viscous force , A = Area , (dv/dx) = velocity gradient
η = F / A(dv/dx) .
SI unit of Coefficient of viscosity (η) of liquid is kg m-1 s-1.