Physical Quantities and Units
by Kwan Yiu Tsun
1. Measuring Length
1.1. The Metre Rule (precision = 1mm)
1.2. Vernier Calipers (precision = 0.01cm)
1.3. The Micrometer Screw Gauge (precision = 0.001cm)
2. Mass
2.1. SI unit is kilogram
2.2. Measure mass with electronic beam balance
2.3. Precision is 0.1g
2.4. Mass and weight is differnet
3. Time
3.1. SI unit is seconds
3.2. 9 192 631 700 times the period of oscillation of radiation from the cesium atom
3.3. Measured with stopwatch (precision = 0.1s)
4. Physical Quantities and Base Unit
4.1. Length (metre) m
4.2. Mass (kilogram) kg
4.3. Time (second) s
4.4. Electric Current (ampere) A
4.5. Thermodynamic temperature (kelvin) K
4.6. Luminous intensity (candela) Cd
4.7. Amount of substance (mole) mol
5. Prefixes and Abrreviation
5.1. tera - T
5.2. giga - G
5.3. mega - M
5.4. kilo - k
5.5. hecto - h
5.6. deka - da
5.7. deci - d
5.8. centi - c
5.9. milli - m
5.10. micro - u
5.11. nano - n
5.12. pico - p
5.13. femto f