Question

The number of significant figures in $1.217\times {10}^{-4}$ is

• A. $1$
• B. $2$
• C. $3$
• D. $4$

Answer 1

The correct option is D $4$

We know that,
$1.$ All non-zero digits are significant figures.
$2.$ All zeros between non-zero digits are significant figures.
$3.$ In scientific notation, $a\times {10}^x$, we consider the significant figures of $a$.
Based on above rules, there is $4$ significant figures in the given number.