Physical Units and Quantities

1. SI unit

1.1. general unit

1.2. recommended unit

1.3. widely used unit

2. numerical prefixes

2.1. tera =10'12

2.2. giga=10'9

2.3. mega=10'6

2.4. kilo=10'3

2.5. hecto=10'2

2.6. deka=10'1

2.7. deci=10'-1

2.8. centi=10'-2

2.9. milli=10'-3

2.10. micro=10'-6

2.11. nano=10'-9

2.12. pico=10'-12

2.13. fento=10'-15

3. basic quantities

3.1. mass

3.1.1. SI unit:kilogram

3.1.2. measuring instrument

3.1.2.1. beam balance

3.1.2.2. sliding balance

3.2. time

3.2.1. SI unit: second

3.2.2. measuring instrument

3.2.2.1. digital stopwatch

3.2.2.2. sundial

3.3. electric current

3.4. temperature

3.5. luminous intensity

3.6. amount of substance

3.7. Length

3.7.1. SI unit: metre

3.7.2. measuring instrument

3.7.2.1. metre rule, accuracy 1mm

3.7.2.2. vernier caliper, accuracy 0.1mm

3.7.2.3. micrometer screw gauge accuracy 0.01mm

3.7.2.3.1. http://www.youtube.com/watch?v=4Buq4Zwi1Q0&hl=en-GB&gl=S

3.7.3. definition of metre

3.7.3.1. distance of light traveled in 1/299792458 of a second

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