🔍 Key Concepts

• How to read a vernier caliper: main scale reading plus vernier scale reading • Identifying the last main-scale mark to the left of the vernier zero • Finding which vernier line exactly lines up with a line on the main scale

💭 Think About

• First, look at figure E and decide what the main scale reading is at the zero mark of the vernier (ignore the vernier numbers at this step). About how many inches and tenths is that? • Next, scan along the vernier scale on top and find the single line that is in perfect alignment with a line on the lower main scale. What is the vernier number at that line, and what increment does each vernier division represent? • Combine the main-scale reading and the vernier reading to form a three-decimal-place measurement, then compare which of the choices is closest to that combined value.

✅ Before You Answer

• Be sure you are reading the main scale from left to right and not confusing it with the vernier numbers. • Confirm which main-scale inch mark the vernier zero has just passed (it should be between 3 and 4 inches in figure E). • Verify how much each vernier division adds (for many exam calipers it is 0.001 inch per vernier division, but confirm from the scale), then multiply that by the aligned vernier number before adding it to the main-scale reading.