# 1 Measurements and their errors

1 Measurements and their errors

1.1 Use of SI units and their prefixes

Fundamental (base) units.
Use of mass, length, time, quantity of matter, temperature, electric current and their associated SI units.
SI units derived.
Knowledge and use of the SI prefixes, values and standard form.
The fundamental unit of light intensity, the candela, is excluded.
Students are not expected to recall definitions of the fundamental quantities.
Dimensional analysis is not required.
Students should be able to use the prefixes: T, G, M, k, c, m, μ, n, p, f, Students should be able to convert between different units of the same quantity, eg J and eV, J and kW h.

1.2 Limitation of physical measurements

Random and systematic errors.
Precision, repeatability, reproducibility, resolution and accuracy.
Uncertainty:
Absolute, fractional and percentage uncertainties represent uncertainty in the final answer for a quantity.
Combination of absolute and percentage uncertainties.
Represent uncertainty in a data point on a graph using error bars.
Determine the uncertainties in the gradient and intercept of a straight-line graph.
Individual points on the graph may or may not have associated error bars.

1.3 Estimation of physical quantities

Orders of magnitude.
Estimation of approximate values of physical quantities.