Question

What is the number of significant figures in \( 420.00040 \times 10^{-3} \)?

Hint:

When counting significant figures, remember that all non-zero digits, any zeros between them, and trailing zeros after a decimal point are significant.

Answer 1

Step 1: Identify the significant figures.
In the number \( 420.00040 \times 10^{-3} \), the significant figures are those digits that provide meaningful information about the precision of the number. The number \( 420.00040 \) has: - \( 4 \), \( 2 \), and \( 0 \) as significant digits. - The decimal point after the last zero indicates that the trailing zeros are significant. Thus, the significant digits in \( 420.00040 \) are \( 4, 2, 0, 0, 0, 0, 4, 0 \).
Step 2: Conclusion.
Therefore, the number of significant figures is \( 8 \).