Free SI Units List PDF for Physics, Chemistry, Electrical, and Exams
The International System of Units, known as SI Units, is the global standard for measurement in science, engineering, and education. Understanding the SI units list is crucial for students, professionals, and anyone preparing for competitive exams like JEE, NEET, CBSE, State Boards, and SSC. This guide breaks down the complete SI units list for physics, chemistry, math, and electrical concepts, and explains why strict unit consistency is vital in calculations and scientific communication.
What Are SI Units? Significance in Science & Exams
SI (Système International d’Unités) units are internationally recognized units for quantifying physical and chemical properties. The SI units list creates a consistent measurement system across the world, ensuring accuracy for research, industry, and academic assessments. Whether it's physics or chemistry, using SI units like metre, kilogram, second, ampere, and mole helps eliminate confusion and standardizes data in both classroom and real-world scenarios.
- Base units form the foundation for all measurements.
- Derived units are combinations of base units through mathematical relations.
- Every physical quantity must be given with its correct SI unit in exams and calculations.
- Mixing SI and non-SI units may lead to incorrect results and mark deductions.
SI Units List: The 7 Fundamental Base Units
| Physical Quantity | SI Unit Name | Symbol |
|---|---|---|
| Length | metre | m |
| Mass | kilogram | kg |
| Time | second | s |
| Electric Current | ampere | A |
| Temperature | kelvin | K |
| Amount of Substance | mole | mol |
| Luminous Intensity | candela | cd |
These seven SI base units are the fundamental building blocks in the SI units list in physics and are essential for all scientific and mathematical calculations. For example, the metre is the SI unit of length, while the kilogram measures mass.
SI Derived Units: Common Examples and Relationships
Beyond base quantities, physics, chemistry, and electrical calculations require SI derived units. These are formed by combining base units through mathematical relationships.
| Derived Quantity | SI Unit Name | Expression in Base Units |
|---|---|---|
| Force, Weight | newton (N) | kg·m·s-2 |
| Energy, Work | joule (J) | kg·m2·s-2 |
| Power | watt (W) | kg·m2·s-3 |
| Pressure, Stress | pascal (Pa) | kg·m-1·s-2 |
| Frequency | hertz (Hz) | s-1 |
| Electric Charge | coulomb (C) | A·s |
| Potential Difference | volt (V) | kg·m2·s-3·A-1 |
| Resistance | ohm (Ω) | kg·m2·s-3·A-2 |
| Capacitance | farad (F) | kg-1·m-2·s4·A2 |
| Magnetic Flux Density | tesla (T) | kg·s-2·A-1 |
| Radioactivity | becquerel (Bq) | s-1 |
In exams, calculations involving force, energy, and electricity depend on these SI derived units. For instance, newton is the SI unit for force and is expressed as kg·m·s-2. Practicing unit conversions and derivations—like those explained at force vs. pressure—is essential for mastering numericals in physics and chemistry.
SI Units List Used in Physics, Chemistry, and Math
Below is a quick-reference SI units table that features the most widely used quantities and their SI units. These are core for school (class 9 & 11), competitive exams and academic projects.
| Physical Quantity | SI Unit | Abbreviation |
|---|---|---|
| Length | metre | m |
| Mass | kilogram | kg |
| Time | second | s |
| Temperature | kelvin | K |
| Electric Current | ampere | A |
| Amount of Substance | mole | mol |
| Luminous Intensity | candela | cd |
| Force | newton | N |
| Energy/Work | joule | J |
| Power | watt | W |
| Pressure | pascal | Pa |
| Frequency | hertz | Hz |
This standardized SI units list for physics and allied sciences underpins all measurement systems and is crucial for concepts in unit conversion, chemistry equations, and electrical quantities.
Quick Rules for Using SI Units in Exams
- Always include the SI unit with every numerical answer.
- Convert all measurements into SI units before solving problems.
- Never mix SI units with non-SI units in calculations.
- Marking errors can occur if units are missing or inconsistent.
Reviewing the motion basics for class 9 or deeper unit problems for class 11? Mastery over SI units and their symbols will elevate your accuracy and understanding.
SI Units List in Chemistry and Electrical Sciences
The SI units list is not just central to physics, but also vital in chemistry and electrical engineering. Important electrical SI units include:
- Potential Difference: volt (V)
- Resistance: ohm (Ω)
- Capacitance: farad (F)
- Inductance: henry (H)
- Electric Charge: coulomb (C)
In chemistry, the SI unit of amount of substance is the mole (mol), crucial for stoichiometry and reactions. For more contexts and conversions, refer to Avogadro’s number or energy units in detail.
SI Units List by Language & Class
Whether you’re searching for SI units list in Hindi, Kannada, or targeting SI units list class 9 and class 11, the foundation remains universal. Exam question patterns demand the accurate use of SI symbols and values in all regions and languages.
Tips for Memorizing the SI Units List
- Create summary tables for quick revision.
- Regularly solve numericals using correct SI units.
- Use flashcards for symbols and conversion tips.
- Understand derivations deeply – like seeing how physics formulas relate to base SI units.
Conclusion: The SI Units List – The Backbone of Measurement
The SI units list forms the language of science, linking classroom concepts with real-world applications in physics, chemistry, math, and engineering. Precision in using base and derived SI units ensures your answers are universally accepted in every board or competitive exam. Make the habit of verifying, writing, and converting all quantities to their SI equivalents for success in any scientific field.
For more insights into SI units, physical quantities, and their roles in class-wise studies, explore the full SI units page or get ahead with targeted chapter resources like units and measurements MCQs.
FAQs on Complete SI Units List for Physics, Chemistry & More
1. What are SI units?
SI units are the internationally accepted standard units of measurement used for scientific and technical purposes worldwide. These units provide consistency and accuracy across all fields of study.
- SI stands for Système International d'Unités.
- Examples of basic SI units include meter (m) for length, kilogram (kg) for mass, and second (s) for time.
- SI units ensure universal understanding and easy unit conversion in science.
2. How many SI base units are there and what are they?
There are seven SI base units that form the foundation of the International System of Units. These are:
- Meter (m) – length
- Kilogram (kg) – mass
- Second (s) – time
- Ampere (A) – electric current
- Kelvin (K) – thermodynamic temperature
- Mole (mol) – amount of substance
- Candela (cd) – luminous intensity
3. Why are SI units important in science?
SI units are crucial in science because they provide a universal system of measurement, making scientific results consistent and comparable globally.
- They eliminate confusion arising from differing measurement systems.
- Ensure uniform communication of scientific data.
- Facilitate accurate calculations and repeatable experiments.
4. What is the SI unit of force?
The SI unit of force is the newton (N).
- One newton is defined as the force required to accelerate a mass of one kilogram at a rate of one meter per second squared (1 N = 1 kg·m/s²).
5. List any five derived SI units with their physical quantities.
Derived SI units are combinations of base units used to measure other physical quantities. Five examples include:
- Newton (N) – force
- Joule (J) – energy or work
- Watt (W) – power
- Pascal (Pa) – pressure
- Coulomb (C) – electric charge
6. What is the SI unit of temperature?
The SI unit for temperature is the kelvin (K).
- Kelvin measures absolute temperature starting from absolute zero.
- It is widely used in scientific experiments and equations.
7. Are litre and tonne SI units?
No, litre and tonne are not official SI base units, but they are accepted for use with the SI system.
- 1 litre (L) = 1 cubic decimetre (dm³).
- 1 tonne (t) = 1000 kilograms (kg).
8. Why is the kilogram the only SI unit with a prefix?
The kilogram is the only SI base unit with a prefix because the original definition was based on a physical object – the mass of a platinum-iridium cylinder.
- All other SI base units are defined without prefixes.
- Smaller and larger masses use prefixes like milligram and megagram respectively.
9. What is the difference between base units and derived units in SI?
Base units are the fundamental units in SI from which all other units are derived, while derived units are combinations of base units.
- Examples of base units: meter, second, kilogram
- Examples of derived units: joule (J = kg·m²/s²), pascal (Pa = N/m²)
10. How do you convert between non-SI units and SI units?
Converting between non-SI units and SI units involves using conversion factors based on the relationship between the units.
- Multiply or divide by the appropriate factor.
- Example: 1 inch = 2.54 centimeters (SI unit for length).
- Keep unit consistency in all scientific calculations.
