Question 37E2

Specific gravity measures the density of the electrolyte in a lead-acid battery relative to water. When the electrolyte, a sulfuric acid solution, is heated, it expands. As its volume increases while its mass remains constant, its density decreases (density = mass/volume). Since specific gravity directly reflects this density, a lower density at higher temperatures results in a lower specific gravity reading. Therefore, temperature compensation is crucial for accurate specific gravity measurements. Option A is incorrect because expansion leads to lower density, not higher. Option C is incorrect as temperature significantly affects fluid density. Option D is incorrect; lower temperatures would cause the electrolyte to contract, increasing its density and thus specific gravity.