Q.10 The number of significant figures in a reported measurement of 0.00361 is
(A) 3
(B) 4
(C) 5
(D) 6

The number of significant figures in 0.00361 is 3.
Leading zeros before non-zero digits in decimal numbers do not count toward significant figures. The digits 3, 6, and 1 are the only significant ones here.​

Rules Recap

Significant figures indicate measurement precision. Key rules include: all non-zero digits count; zeros between non-zero digits count; leading zeros (before the first non-zero digit) do not count; trailing zeros after the decimal count.​

Option Analysis

• (A) 3: Correct. In 0.00361, zeros before 3 are leading and insignificant; 3, 6, 1 count.​

• (B) 4: Incorrect. No fourth digit qualifies; the decimal adds no extra significance here.​

• (C) 5: Incorrect. Counts all digits including leading zeros, violating the leading zero rule.​

• (D) 6: Incorrect. Includes every digit and decimal point, ignoring all standard rules.​

The number of significant figures in 0.00361 is a common query in CSIR NET Life Sciences preparation, testing precision in measurements for biochemistry and data analysis. Understanding this ensures accurate reporting in experiments like enzyme kinetics or genetic quantification.​

Why 3 Significant Figures?

Apply rules to 0.00361:

• Leading zeros (0.00) are placeholders, not significant.​

• Non-zero digits 3, 6, 1 are significant.​
  In scientific notation, it’s 3.61×10−33.61×10−3, confirming 3 sig figs.​

Common Mistakes in CSIR NET

Students often count leading zeros, picking 5 or 6. Practice with similar numbers like 0.0035 (2 sig figs) or 0.0216 (3 sig figs).​

Quick Reference Table

Master significant figures rules for CSIR NET success in quantitative genetics and stats.​