Question

If the length of a rod is measured as 830600 mm, then the number of significant figures in the measurement is

• A. 5
• B. 3
• C. 6
• D. 4

Hint:

To avoid ambiguity with trailing zeros, it's best to express the number in scientific notation. In this case, \(8.306 \times 10^5\) mm clearly shows 4 significant figures. If it were written as \(8.30600 \times 10^5\) mm, it would have 6 significant figures.

Answer 1

The Correct Option is D

Step 1: Rules for Significant Figures: To determine the number of significant figures in a measurement, we follow these standard rules: 1. Non-zero digits: All non-zero digits are always significant. 2. Trapped zeros: Zeros occurring between two non-zero digits are always significant. 3. Trailing zeros (No Decimal): In a number without a decimal point, trailing zeros (zeros at the end) are generally not considered significant unless specified by a measurement error or scientific notation. They usually indicate the order of magnitude. 4. Trailing zeros (With Decimal): Trailing zeros in a number containing a decimal point are significant.
Step 2: Analyzing the given value: The measured value is 830600 mm.
The digits 8, 3, and 6 are non-zero. (3 significant figures so far).
The zero between 3 and 6 is a trapped zero. (1 more significant figure).
The two zeros at the end (trailing zeros) are in an integer with no decimal point. Therefore, they are not significant.

Step 3: Final Count: The significant digits are 8, 3, 0, and 6. Total count = 4.