Specific gravity is defined as the ratio of a liquid's density to the density of water.

• A. True
• B. False
• C. Only at standard conditions
• D. Depends on temperature

Answer: (A)

Specific gravity compares how dense a liquid is to the density of water. It’s defined as the ratio ρ_liquid / ρ_water, using densities at the same temperature, which makes it a dimensionless quantity. Because water’s density changes with temperature, the numerical value of the ratio can vary depending on the reference temperature used (with 4°C commonly chosen for accuracy). So the statement is true: SG is the density of a liquid relative to water’s density.