Units & Measurements
Class 11 · Units & Measurements
Least Count & Zero Error
Apply zero-error correction to raw instrument readings — both positive and negative zero error.
Key Notes
01
Zero error: reading when the instrument shows zero but the actual is nonzero.
02
Positive zero error: instrument reads above zero → SUBTRACT from measurements.
03
Negative zero error: reads below zero → ADD to measurements.
04
Corrected reading = observed − zero error.
Formulas
Correction
Applies to calipers, screw gauges, etc.
Important Points
Always measure zero error BEFORE taking the actual measurement.
Least Count & Zero Error 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.