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Measurements and their errors - Coggle Diagram
Measurements and their errors
SI units
Mass (kilograms)
Temperature (kelvin)
Time (seconds)
Current (amperes)
Length (metres)
Amount of substance (mole)
Coversions
J --> eV = / (1.6*10^-19)
J --> kWh = / (3.6*10^6)
Errors
Random error - An unpredictable fluctuation or variation in results or measurements (affect precision)
Precision - how close measurements are to each other
Systematic errors - consistent, repeatable inaccuracies or fluctuations in measurement or data that skew all readings in one direction (affect accuracy)
Accuracy - how far a result is from the accepted value
Uncertainties
Absolute uncertainty - the margin of error in a measurement expressed in the same physical units
Percentage uncertainty - expresses the margin of error as a proportion to the measurement
Percentage uncertainty = (Absolute uncertainty / measured value) * 100%
Fractional uncertainty - the margin of error in a measurement as a fraction
Fractional uncertainty = Absolute uncertainty / Measured value
Combining uncertainties
Adding uncertainties - change in y = change in a + change in b
Estimation of Physical Quantities
Peta (P) = 10^15,
Tera (T) = 10^12,
Giga (G) = 10^9,
Mega (M) = 10^6,
Kilo (K) = 10^3,
milli (m) = 10^-3,
micro = 10^-6,
nano (n) = 10^-9,
pico (p) = 10^-12,
femto = 10^-15