The significant figures in 0.00051 are

The correct answer is Option 2.

Key Points

• The number 0.00051 has 2 significant figures (5 and 1).
• Leading zeros in a decimal number (zeros before the first non-zero digit) are not considered significant.
• Significant figures are used to indicate the precision of a measurement or calculation in science and mathematics.
• In the case of 0.00051, the digits 5 and 1 are the only meaningful digits contributing to the precision of the number.

Additional Information

• Definition of Significant Figures:
  • Significant figures are the digits in a number that are reliable and necessary to indicate the precision of that number.
  • They include all non-zero digits, any zeros between significant digits, and trailing zeros in the decimal portion.
• Rules for Identifying Significant Figures:
  • All non-zero digits are significant (e.g., 123 has 3 significant figures).
  • Any zeros between non-zero digits are significant (e.g., 1002 has 4 significant figures).
  • Leading zeros are not significant (e.g., 0.0012 has 2 significant figures).
  • Trailing zeros in a decimal number are significant (e.g., 0.1200 has 4 significant figures).
• Purpose of Significant Figures:
  • They are used to express the precision of measured or calculated values.
  • In scientific calculations, they help maintain consistency and avoid overestimating the accuracy of results.
• Examples of Significant Figures:
  • Number 0.00456 has 3 significant figures (4, 5, 6).
  • Number 23000 has 2 significant figures unless written as 2.3 × 10⁴, which clarifies its precision.