🔍 Key Concepts

• Specific gravity as an indicator of state of charge in a lead‑acid battery • The typical specific gravity range for a fully charged lead‑acid cell used on vessels • The instrument used to measure electrolyte specific gravity vs. the one used to measure voltage

💭 Think About

• Think about which values of specific gravity are associated with a fully charged cell versus discharged or partially charged cells. • Consider which tool directly measures the density of the electrolyte, and which one only measures electrical potential (volts). • Ask yourself: If you wanted to check the state of charge of each cell individually by its electrolyte density, what instrument would you use?

✅ Before You Answer

• Verify which specific gravity value listed is commonly cited in marine electrical references for a fully charged lead‑acid cell. • Confirm which device (from the choices) is designed to measure specific gravity of a liquid, not electrical voltage. • Eliminate any options where the specific gravity value does not match a fully charged condition OR the measuring device does not match the property being measured.