Chapter 2 – Units and Measurement

Here we will provide important units of Physical Quantity and discuss about Measurement.

Absolute Error for nth reading = $\Delta a_n= a_{n}- a_{m}$ = true value - measured value
Mean absolute error= $\dpi{100} \Delta\bar{ a}= \frac{\left | \Delta a_{1} \right |+\left | \Delta a_{2} \right |+....\left | \Delta a_{n} \right |}{n}$
Relative error= $Relative \ \ error=\frac{\Delta{ a}}{a_{m}}$
$Percentage \ \ error=\frac{\Delta{ a}}{a_{m}}\times100$ %
Absolute error in sum (x=a+b) = $\Delta x= \pm \left ( \Delta a+\Delta b \right )$
Absolute error in difference (x=a-b)= $\Delta x= \pm \left ( \Delta a+\Delta b \right )$
Relative error in product (x=a.b)= $\frac{\Delta x}{x}= \pm \left ( \frac{\Delta a}{a} +\frac{\Delta b}{b} \right )$
Relative error in division (x = a/b)= $\frac{\Delta x}{x}= \pm \left ( \frac{\Delta a}{a} +\frac{\Delta b}{b} \right )$