🔍 Key Concepts

• Main scale vs. vernier scale on a vernier caliper and how they combine to give a single reading • How to determine the whole inches and fractional/incremental part from the main scale before looking at the vernier • How to find which vernier graduation lines up exactly with a main-scale line to determine the decimal part

💭 Think About

• First, look at figure A and decide how many whole inches are clearly passed on the main scale just to the left of the zero of the vernier. Which of the choices match that? • Next, determine how many additional vernier divisions beyond that whole-inch mark are indicated by the line that best aligns with a main-scale graduation. How much (in thousandths of an inch) does each vernier division represent for this caliper? • Combine your whole-inch reading with the vernier increment reading. Which answer choice has the correct combination of whole inches and decimal part?

✅ Before You Answer

• Be sure the whole-inch reading comes only from the main scale, not from the vernier numbers inside the window. • Confirm which single vernier line is in perfect alignment with a main-scale line; ignore lines that are close but not exact. • Verify the value of each vernier division (e.g., 0.025 in or 0.050 in) based on how many vernier divisions equal one main-scale division, and check that against the decimal part in the choices.