Question

The respective number of significant figures for the numbers $23.023,0.0003$ and $2.1\times {10}^{-3}$ are

• A. $5,1,2$
• B. $5,1,5$
• C. $5,5,2$
• D. $4,4,2$

Answer 1

The correct option is A

$5,1,2$

Explanation for correct option

$\bullet$Significant figures: Significant figures are the numbers of digits in a value, that contribute to the degree of accuracy of the value.

Rules for significant figures are :

$\bullet$ All non-zero numbers are significant figures.

$\bullet$ Zeros between two non-zero digits are significant.

$\bullet$ All zeros to the right of decimal point and to the left of non-zero digit are not significant.

$\bullet$ All zeros to the right of decimal are significant only if a non-zero digit does not follow them.

$\bullet$ All zeros to the right of non-zero digit after the decimal point are significant.

So, in $23.023$number of significant figures are $5$

In $0.0003$ number of significant figure is $1$

And in $2.1\times {10}^{-3}$ number of significant figures are $2$

Hence, the correct option is option(A) i.e. $5,1,2$