Discoverers and Discovery Years of Some Chemical Elements
| S.N. | Element Name | Discoverer | Year of Discovery |
|---|---|---|---|
| 1. | Hydrogen (H) | H. Cavendish | 1766 |
| 2. | Helium (He) | Lockyer | 1868 |
| 3. | Nitrogen (N) | Rutherford | 1772 |
| 4. | Oxygen (O) | Scheele and Priestley | 1772–1774 |
| 5. | Sodium (Na) | Davy | 1807 |
| 6. | Magnesium (Mg) | Davy | 1808 |
| 7. | Aluminium (Al) | Oersted and Wöhler | 1825–1827 |
| 8. | Silicon (Si) | Berzelius | 1824 |
| 9. | Chlorine (Cl) | C.W. Scheele | 1774 |
| 10. | Argon (Ar) | Ramsay and Rayleigh | 1894 |
Some Physical Quantities and Their Units
| Physical Quantity | Unit |
|---|---|
| Intensity of Sound | Decibel (dB) |
| Force | Newton (N), Dyne |
| Heat | Joule (J) |
| Work/Energy | Joule (J) |
| Power | Watt (W) |
| Momentum | Kilogram meter per second (kg-m/s) |
| Pressure | Pascal (Pa) |
| Earthquake | Richter Scale |
| Frequency | Hertz (Hz) |
| Density | Kilogram per cubic meter (kg/m³) |
| Power of Lens | Dioptre (D) |
| Electric Potential | Volt (V) |
| Electric Current | Ampere (A) |
| Radioactivity | Curie (Ci) |
| Luminous Intensity | Candela (cd) |
| Thermodynamic Temperature | Kelvin (K) |
Tags:
Objective
