1.1 UNITS AND BASIC
QUANTITIES
LENGTH
UNIT
Metre (m)
DEFINITION
Distance travelled by light in a
vacuum during a specific time
SUBMULTIPLES
1 Decimetre (dm)
10
1 Centimetre (cm)
10
1 Millimetre (mm)
10
-1 m
-2 m
-3 m
or (0.1m)
or (0.01m)
or (0.001m)
LENGTH
AREA
• Area = Length x Breadth
• Unit : square metre (𝑚2 )
VOLUME
• Volume = Length x Breadth x Height
• Unit : cubic metre (𝑚3 )
• Volume of circle =
4
𝜋𝑟 3
3
• Volume of cylinder = 𝜋𝑟 2 ℎ
TIME
• Unit : Second (s)
• Time-measuring devices rely on
some kind of constantly repeating
oscillation.
• Accuracy can be improved by
measuring longer time intervals