Question

The length and breadth of a rectangle are $(5.7\pm 0.1)cm$ and $(3.4\pm 0.2)cm$. Calculate area of the rectangle with error limits.

• A.
• B.
• C.
• D.

Answer 1

The correct option is C

$Here,I=(5.7\pm 0.1)cmb=(3.4\pm 0.2)cmAreaA=1\times b=5.7\times 3.4=19.38c{m}^2\left(roundingofftotwosignificantfigures\right)\therefore \frac{(\Delta 1}{1}+\frac{\Delta b}{b}=\pm (\frac{0.1}{5.7}+\frac{0.2}{3.4})=\pm \left(\frac{0.34+1.14}{5.7\times 3.4}\right)\frac{\Delta A}{A}=\pm \frac{1.48}{19.38}\Rightarrow \Delta A=\pm \frac{1.48}{19.38}\times A=\pm \frac{1.48}{19.38}\times 19.38=\pm 1.48$