Question

a. Write 30685 correct to 3 significant figures
b. Write 0.050462 correct to 3 significant figures

Answer 1

Given:

(a)- 30685 and (b)- 0.050462

To Find:

a. Write 30685 correct to 3 significant figures .

b. Write 0.050462 correct to 3 significant figures.

Solution:

To determine the significant figure of a number , 3 points we have to keep in mind;

• Non-zero digit is always significant.
• Any zero between non-zero (significant) digit is significant.
• A final zero in the decimal portion only are significant.

(a)- 30625;

It has 5 significant figure. To correct it to 3 significant figures

we have ,

$\[\begin{gathered} \Rightarrow 30685 \hfill \\ = 3.0685 \times {10^4} \hfill \\ = 3.07 \times {10^4} \hfill \\ \end{gathered} \]$

Hence, 3.07 × $10^{4}$ have 3 significant figures.

(b)- 0.050462

It has  5 significant figures . To correct it to 3 significant figures

we have,

$\[\begin{gathered} \Rightarrow 0.050462 \hfill \\ = 5.0462 \times {10^{ - 2}} \hfill \\ = 5.05 \times {10^{ - 2}} \hfill \\ \end{gathered} \]$

Hence, 5.05 × $10^{-2}$ have 3 significant figures.