Which instrument is used to test the specific gravity of the prepared anti-freeze solution?

Which instrument is used to test the specific gravity of the prepared anti-freeze solution?

• A. Refractometer
• B. Multimeter
• C. Pitot gauge
• D. Tachometer

Answer: (A)

Testing the antifreeze solution focuses on its concentration, since the glycol content determines the solution’s density and freezing point. A refractometer is used because it measures the refractive index of a liquid, and glycol–water mixtures have a predictable relationship between refractive index and glycol concentration. By placing a small sample on the prism and reading the index, you can quickly determine the glycol amount and verify that the solution meets the required specification for the system’s specific gravity and freezing performance. The other instruments don’t assess liquid concentration: a multimeter checks electrical properties, a Pitot gauge measures flow pressure, and a tachometer measures rotational speed.

Testing the antifreeze solution focuses on its concentration, since the glycol content determines the solution’s density and freezing point. A refractometer is used because it measures the refractive index of a liquid, and glycol–water mixtures have a predictable relationship between refractive index and glycol concentration. By placing a small sample on the prism and reading the index, you can quickly determine the glycol amount and verify that the solution meets the required specification for the system’s specific gravity and freezing performance. The other instruments don’t assess liquid concentration: a multimeter checks electrical properties, a Pitot gauge measures flow pressure, and a tachometer measures rotational speed.