What is the formula to find specific gravity?

The correct formula for specific gravity is given by the relationship of the weight of a substance compared to the weight of an equal volume of water. Specific gravity (SG) is a dimensionless quantity that provides a measure of how dense a substance is relative to water. Since water has a density of 1 g/cm³ at 4°C, this makes it a convenient standard for comparison.

In this context, specific gravity is calculated as the weight of the substance divided by the weight of an equal volume of water. This means that if you take a certain volume of a substance and weigh it, you can then compare that weight to the weight of the same volume of water. If the specific gravity is greater than 1, the substance is denser than water; if it is less than 1, the substance is less dense than water.

The other formulas do not represent the correct calculation for specific gravity. For example, dividing the volume of the substance by the weight of water does not yield a meaningful comparison of density. The correct relationship clearly defines how weight comparisons are made, making the identification of option C as the accurate formula essential for understanding specific gravity.