Q. A physical quantity $A$ is related to four observables $a,\ b,\ c\ and\ d$ as follows $\ A = \frac{a^{2}b^{3}}{c\sqrt{d}}$ The percentage errors of measurement in $a,\ b,c\ and\ d$ are 1%, 3%, 2% and 2% respectively. What is the percentage error in the quantity $A?$

A) 12%
B) 7%
C) 5%
D) 14%
Explanation

Percentage error in $\ A = \left( 2\frac{\mathrm{\Delta}a}{a} + 3\frac{\mathrm{\Delta}b}{b} + \frac{\mathrm{\Delta}c}{c} + \frac{1}{2}\frac{\mathrm{\Delta}d}{d} \right) \times 100\%$ $\ = 2 \times 1 + 3 \times 3 + 2 + \frac{1}{2} \times 2$ $= 2 + 9 + 2 + 1 = 14\%$

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.