A physical quantity P is related to four observables a, b, c and d as follows : The percentage errors of measurement in a, b, c and d are 1%, 3%, 4% and 2%, respectively. What is the percentage error in the quantity P ? If the value ofP calculated using the above relation turns out to be 3.763, to what value should you round off the result?
The quantity used as a standard of measurement is called unit.
To get the complete knowledge of any physical quantity, measurement is needed. Measurement of any physical quantity involves comparison with a certain basic, arbitrarily chosen, internationally accepted reference standard called unit. Knowledge without measurement is incomplete and unsatisfactory.