1.1 Physical Quantities O Level

A physical quantity is a one that can be ___________.

It consists of a magnitude and a unit.

• counted

• seen

• measured

• derived

Which of these consists only of base quantities?

Remember to know your six base quantities!

• Length, current, mole

• Temperature, force, mass

• Second, length, mass

• Time, current, amount of substance

What is the unit of force in terms of the SI base units?

Make sure you know what your base units are!

•  $kg\ m^2\ s^{-2}$  

•  $kg\ m\ s^{-2}$  

•  $N$  

•  $kg\ m\ s^{-1}$  

If the earth is $150\ Gm$ away from the sun, what is this in metres?

•  $1.5\times10^{11}\ m$  

•  $1.5\times10^{12}\ m$  

•  $1.5\times10^{13}\ m$  

•  $1.5\times10^{14}\ m$  

Arrange the following prefixes in order of increasing powers of 10.

• $\mu,\ n,\ c,\ m$

• $c,\ m,\ \mu,\ n$

• $n,\ \mu,\ m,\ c$

• $m,\ c,\ n,\ \mu$