Question

Consider the following:
a) 0.0025
b) 500.0
c) 2.0034
Number of significant figures in A, B and C respectively are

• A. 5, 4, 4
• B. 2, 4, 2
• C. 4, 3, 2
• D. 2, 4, 5

Hint:

To easily identify significant figures, try writing the number in scientific notation. For example, \( 0.0025 \) becomes \( 2.5 \times 10^{-3} \) (2 digits), and \( 500.0 \) becomes \( 5.000 \times 10^2 \) (4 digits). The digits in the coefficient are always the significant ones!

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Significant figures represent the digits in a measurement that are known with certainty plus one final estimated digit. Rules exist to determine if a zero is significant.
Step 2: Detailed Explanation:
a) 0.0025: Leading zeros (zeros to the left of the first non-zero digit) are never significant. They are placeholders. Significant digits: 2, 5. Count = 2.
b) 500.0: Trailing zeros are significant if there is a decimal point present. The decimal point implies a specific degree of precision. Significant digits: 5, 0, 0, 0. Count = 4.
c) 2.0034: Captured zeros (zeros between non-zero digits) are always significant. Significant digits: 2, 0, 0, 3, 4. Count = 5.
Step 3: Final Answer:
The correct sequence is 2, 4, 5.