Q.
The diameter of a given wire is measured by a screw gauze. The three measurements of the diameter give the reading in cm as 0.036,0.035 and 0.037. What is the percentage error of the measurement?
Mean measurement of wire =30.036+0.035+0.037=0.036cm
Taking 0,036cm as the true value, the absolute errors (true value - measured value) in the three readings taken are 0.036−0.036=0.036−0.035=0.001cm0.036−0.037=−0.001cm
The (maximum) mean absolute error is δdmax=30+001+0.001=0.00066cm
The percentage error is =0.0360.00066×100=1.8%