To determine the number of significant figures in a given measurement, we need to count all the digits that are considered reliable and necessary to indicate the precision of the measurement. Significant figures include all non-zero digits, any zeroes between significant digits, and trailing zeros in a decimal number.
Let's analyze the given measurement: [tex]\( 3.00 \times 10^{-4} \)[/tex] meters.
1. Identify the significant digits in the base number:
- The number [tex]\(3.00\)[/tex] is in decimal form.
- The digit [tex]\(3\)[/tex] is a non-zero digit; therefore, it is significant.
- The zeros that directly follow the digit [tex]\(3\)[/tex] are trailing zeros in a decimal number, which means they are also significant because they indicate the precision of the measurement.
2. Count the significant figures:
- The digit [tex]\(3\)[/tex] is significant.
- Both trailing zeros (after the decimal point) are significant.
- Therefore, there are three significant digits.
The exponent ([tex]\(10^{-4}\)[/tex]) does not affect the number of significant figures; it only scales the number.
Hence, the measurement [tex]\(3.00 \times 10^{-4} \)[/tex] meters has 3 significant figures.
Therefore, the correct answer is:
(A) 3