Q1: Pick up the correct statement from the following :

ANS:D - all the above.

The correct statement from the options provided is: The fluids which do not follow the linear relationship between shear and rate of strain are known as non-Newtonian fluids. This statement accurately describes non-Newtonian fluids, which exhibit viscosity that varies with the applied stress or shear rate, unlike Newtonian fluids where viscosity remains constant regardless of the applied stress. The other statements provided are not entirely correct:

• The first statement should be: "The fluids which follow the linear relationship between shear stress and rate of strain are known as Newtonian fluids."
• The third statement is about substances exhibiting yield strains, which are often referred to as Bingham plastics or simply viscoplastic materials, rather than all plastics.