Explain Absolute Error, Relative Error and Percentage Error.

Vedclass pdf generator app on play store
Vedclass iOS app on app store

$(a)$ Absolute Error:

The magnitude of the difference between the individual measurement and the true value of the quantity is called the absolute error of the measurement.

It is denoted by $|\Delta a|$.

In absence of any other method, we consider arithmetic mean as true value.

Consider physical quantity ' $a$ '. Its measurement be $a_{1}, a_{2}, a_{3}, \ldots, a_{n}$ Average value,

$\therefore a_{\text {mean }}=\frac{a_{1}+a_{2}+a_{3}+\ldots a_{n}}{n}$ OR

$\sum^{n} a_{i}$

$=\frac{i=1}{n} \text { where, } i=1,2,3, \ldots, n$

$(b)$ Absolute error in measurement

$\Delta a_{1}=a_{1}-a_{\text {mean }}$

$\Delta a_{2}=a_{2}-a_{\text {mean }}$

$: \quad: \quad:$

$\Delta a_{n}=a_{n}-a_{\text {mean }}$

$\Delta a$ may be positive or negative.

Average absolute error is denoted by $(\Delta a)_{\text {mean }}$

$=\frac{\left|\Delta a_{1}\right|+\left|\Delta a_{2}\right|+\ldots\left|\Delta a_{n}\right|}{n}$

$=\frac{\sum_{i=1}^{n}\left|\Delta a_{i}\right|}{n}$

where, $i=1,2,3, \ldots, n$

Physical quantity is represented as,

$a=a_{\text {mean }} \pm(\Delta a)_{\text {mean }}$

$\text { OR } a_{\text {mean }}-\Delta a_{\text {mean }} \leq a \leq a_{\text {mean }}+\Delta a_{\text {mean }}$

Similar Questions

The resistance $R =\frac{ V }{ I },$ where $V =(50 \pm 2) \;V$ and $I=(20 \pm 0.2)\;A.$ The percentage error in $R$ is $x\%$. The value of $x$ to the nearest integer is .........

  • [JEE MAIN 2021]

What is error in measurement, done by any instrument ?

Measure of two quantities along with the precision of respective measuring instrument  $A = 2.5\,m{s^{ - 1}} \pm 0.5\,m{s^{ - 1}}$, $B = 0.10\,s \pm 0.01\,s$ The value of $AB$ will be

A body of mass $(5 \pm 0.5) kg$ is moving with a velocity of $(20 \pm 0.4) m / s$. Its kinetic energy will be

  • [JEE MAIN 2023]

An experiment is performed to obtain the value of acceleration due to gravity $g$ by using a simple pendulum of length $L$. In this experiment time for $100\, oscillations$ is measured by using a watch of $1\, second$ least count and the value is $90.0\, seconds$. The length $L$ is measured by using a meter scale of least count $1\, mm$ and the value is $20.0\, cm$. The  error in the determination of $g$ would be  ........... $\%$

  • [JEE MAIN 2014]