Solution:

? The property of a liquid by which forces are exerted between layers so as to reduce their relative motion is called viscosity.

? The liquids flow in different layers. The layer at the top will be flowing with maximum velocity.

? The lower layer will be flowing with lesser and lesser velocities.

? The reason for this change in velocity from layer to layer is the frictional force between liquid layers.

? Different liquids possess different viscosity.

? Liquids of large viscosity are called viscous liquids. Ex: Glycerine, Honey, Castor oil etc

? Liquids of small viscosity are called mobile liquids. Ex: Water, Kerosene etc

? The viscosity of an ideal fluid is zero.