Which instrument is used to measure viscosity of liquids?

Which instrument is used to measure viscosity of liquids?

• A. Brookfield viscometer
• B. Polarimeter
• C. Refractometer
• D. Flame photometer

Answer: (A)

Measuring how easily a liquid flows—its viscosity—depends on how the liquid resists shearing forces. The Brookfield viscometer is designed for this and does the measurement by rotating a spindle immersed in the liquid at a set speed and sensing the torque required to turn it. That torque is translated into an apparent viscosity value at the chosen shear rate and temperature, typically reported in centipoise. This makes it the appropriate instrument for viscosity.

In contrast, a polarimeter measures how much the plane of polarized light is rotated by a chiral sample, a refractometer gauges how light bends to determine refractive index, and a flame photometer analyzes light emitted from a flame to determine elemental concentrations. These instruments are not used to measure viscosity.