🔍 Key Concepts

• How to read a micrometer caliper: add the sleeve (barrel) reading plus the thimble reading, then any vernier correction • Understanding that each division on a standard inch micrometer thimble usually equals 0.001 inch, and each vernier division (if present) refines this by ten-thousandths (0.0001 inch) • Carefully identifying which sleeve mark is fully visible to the left of the thimble edge, and which thimble/ vernier lines are in exact alignment

💭 Think About

• First, from the horizontal sleeve scale at the bottom of figure A, what is the last full 0.025-inch (or 0.050-inch) mark that is still visible to the left of the thimble edge? • Next, on the vertical thimble scale to the right, which graduation lines up exactly with the horizontal reference line on the sleeve? How many thousandths of an inch does that represent? • Finally, on the vernier (the short numbered scale 0–9), which line best lines up with a line on the thimble? How many ten‑thousandths of an inch does that add to your total?

✅ Before You Answer

• Be sure the sleeve reading you use is the last full mark completely to the left of the thimble edge, not a partially covered one • Confirm that the thimble graduation you pick is the one exactly in line with the reference line; ignore nearby lines that are slightly off • Verify that the vernier alignment adds only a small (0.000x) correction and that your final answer matches one of the choices to the nearest ten‑thousandth of an inch