physical quantities and units

Question 1

what does a physical quantity need

Answer 1

magnitude and unit

Question 2

what are the SI base units

Answer 2

1. meter; m
2. second; s
3. ampere; A
4. kelvin; K
5. mass; kg
6. mole; mol
7. candela; cd

Question 3

prefix for units

Answer 3

pico -12
nano -9
micro -6
milli -3
centi -2
deci 1
kilo 3
mega 6
giga 9
tera 12

Question 4

how to reduce errors

Answer 4

systematic: use instrument with better accuracy and percision
random: do more times and average