Significant Figures Rules for NEET | Short Notes, Tricks & Solved Questions

 - Dr.Sanjaykumar Pawar  

Significant Figures in Physics & Chemistry | NEET Preparation Notes 

Significant Figures Rules and Tricks for NEET: Easy Chart to Remember Counting Rules

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Significant Figures (महत्वपूर्ण अंक) - NEET Smart Notes

Part 1: Questions and Answers

Question: State the number of significant figures in the following:

1. 0.007 m²
2. 2.64 × 10²⁴ kg
3. 0.2370 g cm⁻³
4. 6.320 J
5. 6.032 N m⁻²
6. 0.0006032 m²

Solution:

Question	Explanation	Answer
0.007 m²	Leading zeros are not significant. Only 7 is counted.	1 Significant Figure
2.64 × 10²⁴ kg	All non-zero digits are significant.	3 Significant Figures
0.2370 g cm⁻³	Leading zero ignored. 2,3,7 and final zero after decimal counted.	4 Significant Figures
6.320 J	Final zero after decimal is significant.	4 Significant Figures
6.032 N m⁻²	Zero between non-zero digits is significant.	4 Significant Figures
0.0006032 m²	Starting zeros ignored. Zero between 6 and 3 is significant.	4 Significant Figures

Part 2: Short Notes for Beginners

What are Significant Figures?

Significant figures are the meaningful digits in a measurement. They show the accuracy or precision of a measured value.

Rules of Significant Figures

Rule	Description	Example
1	All non-zero digits are significant.	245 = 3 S.F.
2	Zeros between two non-zero digits are significant.	1002 = 4 S.F.
3	Zeros before the first non-zero digit are not significant.	0.0045 = 2 S.F.
4	Trailing zeros after decimal are significant.	4.500 = 4 S.F.
5	Scientific notation: only digits before power of 10 are counted.	3.20 × 10⁵ = 3 S.F.

Part 3: Mnemonics (याद करने की ट्रिक)

N-Z-B-D Rule

N = Non-zero digits

1 to 9 are always significant.

Z = Zero in between

Zero between two non-zero digits is significant.
Example: 506 = 3 S.F.

B = Before zero

Zeros before the first non-zero digit are ignored.
Example: 0.005 = 1 S.F.

D = Decimal ending zero

Zeros at the end after decimal are significant.
Example: 2.500 = 4 S.F.

Easy Hindi Memory Line:

"शुरुआत का Zero छोड़ो, बीच का Zero पकड़ो, Decimal के बाद का Zero जोड़ो।"

One Line Revision Formula:

START ZERO ❌
MIDDLE ZERO ✅
END ZERO WITH DECIMAL ✅
NON ZERO ALWAYS ✅

NEET Question Solving Strategy

1. सबसे पहले देखें कि Decimal है या नहीं।
2. शुरुआती zeros को ignore करें।
3. Non-zero digits को हमेशा count करें।
4. दो digits के बीच वाले zeros को count करें।
5. Decimal के बाद अंतिम zeros को count करें।

Answer Explanation Format:

Given Number: 0.006030

Leading zeros ignored.

Significant digits: 6, 0, 3, 0

Final Answer = 4 Significant Figures