1.3 International System of Units
The international committee on weights and measures in 1961 recommended the use of a system consisting of seven base units known as the International System of Units, abbreviated as SI. This system is in use all over the world.
Use of SI measurements helps all scientists share and compare their observations and results easily. The seven base units are given in Table 1.2. Their values are fixed with reference to international standards.
Table 1.2: SI Base Units
| Sr. No. | Physical quantity | Unit | Symbol |
|---|---|---|---|
| 1. | Length | metre | m |
| 2. | Mass | kilogram | kg |
| 3. | Time | second | s |
| 4. | Temperature | kelvin | K |
| 5. | Electric current | ampere | A |
| 6. | Intensity of light | candela | cd |
| 7. | Amount of substance | mole | mol |
lightbulbDo You Know? The kilogram is the only base unit that has a prefix.