Units & Measurements
Class 11 · Units & Measurements

Screw Gauge (Micrometer)

Measure thicknesses to 0.001 cm with a circular thimble with 50 divisions.

Run simulation

Key Notes

01

Least count = pitch / number of circular divisions (typically 0.5 mm / 50 = 0.01 mm).

02

Reading = linear-scale reading + (circular-scale reading) × LC.

03

Zero error must be applied: corrected reading = observed − zero error.

Formulas

Least count

Pitch = linear advance per revolution; N = number of divisions on thimble.

Important Points

Backlash error: always rotate in one direction during measurement.

Screw Gauge (Micrometer) notes from sciphylab (also known as SciPhy, SciPhy Lab, SciPhy Labs, Physics Lab). Class 11 physics revision for JEE Mains, JEE Advanced, NEET UG, AP Physics 1/2/C, SAT, and CUET-UG.