Give the number of significant figures of the population of a town which has approximately 5,020,700 people

Analysis of the Question

The question asks for the number of significant figures in the value 5,020,700. To solve this, we must apply the standard rules for counting significant figures in a number containing zeros.

Concept: Rules for Significant Figures

1. Non-zero digits are always significant.
2. Zeros between non-zero digits are always significant (e.g., the '0' in 502 is significant).
3. Leading zeros (zeros at the beginning of a number) are never significant.
4. Trailing zeros in a whole number without a decimal point are generally considered not significant unless specified otherwise (they are placeholders).

Step-by-Step Solution

Let's look at the number: 5,020,700

• 5: Significant (non-zero)
• 0: Significant (it is trapped between 5 and 2)
• 2: Significant (non-zero)
• 0: Significant (it is trapped between 2 and 7)
• 7: Significant (non-zero)
• 00: Not significant (these are trailing zeros in a whole number, serving as placeholders for the hundreds, tens, and units positions).

Counting the significant digits: 5, 0, 2, 0, 7. There are exactly 5 significant figures.

Conclusion

The digits 5, 0, 2, 0, and 7 are significant, while the final two zeros are placeholders. Therefore, the number has 5 significant figures.

Exam Tip

When you see a large number ending in zeros, ignore the trailing zeros if there is no decimal point. Always focus on the "trapped" zeros—they are the ones that usually catch students off guard in JAMB exams!