Physics · Class 11 · Chapter 1
Units and Measurements
10 lessons 86 min 2 simulations
Every number in physics is a comparison with a chosen standard, the unit. This chapter sets up the SI system of seven base units, the rules for reporting a measured value honestly with significant figures, how uncertainties carry into a calculated result, and the dimensions of physical quantities, which let you check an equation and even guess the form of one.
What the exam asks
NEET asks for the number of significant figures in a value, the correct rounding of a product, sum or difference, dimensional formulae of common quantities, and which of several equations is dimensionally possible. Marks are lost by counting trailing zeros wrongly, applying the decimal-place rule to a product (or the significant-figure rule to a sum), and treating a dimensionally correct equation as proven right.
Lessons
10 lessons · 86 min
1Units: base, derived and systemsNCERT §1.17 min2The SI systemNCERT §1.27 min3Significant figuresNCERT §1.38 min4Arithmetic with significant figuresNCERT §1.3.18 min5Rounding offNCERT §1.3.27 min6Uncertainty in calculated resultsNCERT §1.3.311 min 1 sim7Dimensions and dimensional formulaeNCERT §1.4, §1.57 min8Checking dimensional consistencyNCERT §1.6.17 min9Deducing relations by dimensionsNCERT §1.6.211 min 1 sim10Chapter reviewMust-know facts, traps and formulas13 min