Question

The length, breadth and thickness of a block are given by $l=12cm,b=6cm$ and $t=2.45cm$. The volume of the block according to the idea of significant figures should be

• A. $2\times {10}^2$
• B. $2\times {10}^{2}c{m}^3$
• C. $1.763\times {10}^{2}cm$
• D. None of these

Answer 1

The correct option is B $2\times {10}^{2}c{m}^3$

$\text{Step1: Volume calculation}$

Volume of the block, $V=l\times b\times t$

$=12\times 6\times 2.45c{m}^3$

$=1.764\times {10}^{2}c{m}^3$

$\text{Step2: Rounding off the volume according to significant figures}$

For multiplication, the least number of significant figures in any number of the problem determines the number of significant figures in the answer.

Since the minimum number of the significant figures is $1$ in width $\left(6cm\right)$, therefore the volume will also contain only $1$ significant figure.

Therefore, rounding off the volume $(1.764\times {10}^{2}c{m}^3)$ to $1$ significant figure, we get

$V=2\times {10}^{2}c{m}^3$

Hence, Option B is the correct answer.