How many significant figures are present in the measurement 0.020 km?

• A. 4
• B. 3
• C. 1
• D. 2

Answer: (B)

Verified step by step guidance

1. Identify the digits in the measurement 0.020 km and determine which are significant. Remember that leading zeros (zeros before the first nonzero digit) are not significant.
2. In 0.020 km, the first two zeros are leading zeros and are not significant, but the zero after the 2 is a trailing zero in a decimal number, which is significant.
3. Count the significant digits: the digit '2' and the trailing zero after it are significant, as well as the digit '2' itself.
4. Therefore, the number of significant figures in 0.020 km is 3.
5. Recall the general rule: zeros between nonzero digits and trailing zeros in decimal numbers are significant, while leading zeros are not.