What makes a measurement meaningful?
What makes a measurement meaningful?
A physical quantity is something that can be measured and written as a number with a unit. Saying "length = 2.0" is incomplete, because 2.0 m2.0\text{ m}2.0 m, 2.0 cm2.0\text{ cm}2.0 cm and 2.0 km2.0\text{ km}2.0 km are all fundamentally different values.
Step-by-step lessons on Edexcel A Level Physics SI units and physical quantities. Each one builds up to exam-style questions. Physics is one of the most mathematically demanding A Levels -- at least 40% of the marks across the three papers require maths skills at Level 2 (GCSE) standard or above, so build calculation and graph-handling fluency alongside the conceptual content from the start.