Which of the following is NOT a type of non-Newtonian fluid?

• A. Newtonian
• B. Pseudoplastic (shear thinning)
• C. Dilatant (shear thickening)
• D. Bingham plastic

Answer: (B)

The key idea is how viscosity behaves with shear. Newtonian fluids keep a constant viscosity no matter how you apply shear. Non-Newtonian fluids change viscosity as the shear rate changes, or they require a yield stress to start flowing.

Among the options, the fluid with constant viscosity under different shear conditions is the one that is not a non-Newtonian type. The other three are non-Newtonian: pseudoplastic is shear-thinning (viscosity drops as you shear faster), dilatant is shear-thickening (viscosity increases with shear), and Bingham plastic acts like a solid until a yield stress is exceeded, then it flows like a viscous fluid.