- Dr.Sanjaykumar Pawar
Rectangular Sheet Area and Volume Calculation | Significant Figures NEET Guide
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| Significant Figures NEET Notes: Learn measurement rules, area-volume formulas, unit conversion, and numerical solving tricks with easy memory techniques. |
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NEET Concept Notes: Significant Figures, Area and Volume Calculation
Question
The length, breadth and thickness of a rectangular sheet of metal are 4.234 m, 1.005 m and 2.01 cm respectively. Give the area and volume of the sheet to correct significant figures.
Solution (Step by Step)
Given Data:
| Quantity | Value | Significant Figures |
|---|---|---|
| Length | 4.234 m | 4 |
| Breadth | 1.005 m | 4 |
| Thickness | 2.01 cm = 0.0201 m | 3 |
Step 1: Convert Unit
Thickness = 2.01 cm
1 cm = 10-2 m
Thickness = 2.01 × 10-2 m = 0.0201 m
Step 2: Calculate Area
A = 4.234 × 1.005
A = 4.25517 m²
Least significant figures = 4
Area = 4.255 m²
Step 3: Calculate Volume
V = 4.234 × 1.005 × 0.0201
V = 0.085527917 m³
Least significant figures = 3
Volume = 0.0855 m³
Short Notes: Significant Figures
- Significant figures show the accuracy of a measurement.
- Final answer should contain the same number of significant figures as the value having the least significant figures.
- All non-zero digits are always significant.
- Zeros between non-zero digits are significant.
- Starting zeros are not significant.
| Number | Significant Figures |
|---|---|
| 4.234 | 4 |
| 1.005 | 4 |
| 0.0201 | 3 |
Formula Notes
A = l × b
Rectangle Volume:
V = l × b × t
Remember:
- Area uses two dimensions.
- Volume uses three dimensions.
- Always convert units before calculation.
Mnemonics (Easy Memory Tricks)
1. Significant Figures Rule
"Non-zero digits are HERO"
HERO:
- H - Hidden zeros (between numbers) are significant
- E - Ending zeros after decimal can be significant
- R - Real non-zero digits are always significant
- O - Opening zeros are not significant
2. Zero Rule
"शुरू के Zero सोते हैं, बीच के Zero काम करते हैं।"
3. Calculation Method
D-U-F-C-A Method
| Letter | Meaning |
|---|---|
| D | Data पहचानो |
| U | Unit सही करो |
| F | Formula लगाओ |
| C | Calculate करो |
| A | Accuracy (Significant Figures) check करो |
NEET Exam Trick
"पहले Unit, फिर Formula, फिर Calculation, अंत में Significant Figure"
इस तरीके से विद्यार्थी numerical questions को जल्दी और सही तरीके से solve कर सकता है।
