Which of the following instruments is used for measuring the relative density of liquids?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Hydrometer
A hydrometer is specifically designed to measure the relative density or specific gravity of liquids by floating in them.
Lactometer: This is actually a type of hydrometer, but it is specifically designed to measure the relative density and purity of milk.
Decimeter: This is a unit of length (equal to one-tenth of a meter, or 10 cm), not a measuring instrument for liquids.
Orthometer: This is a specialized surveying instrument used for measuring vertical distances or elevations with high precision.