Unit And Dimensions
Measurement of any physical quantity is expressed in terms of an internationally accepted certain basic standard called unit.
- $\quad$ Fundamental Units.
| S.No. | Physical Quantity | SI Unit | Symbol |
|---|---|---|---|
| 1 | Length | Metre | $\mathrm{m}$ |
| 2 | Mass | Kilogram | $\mathrm{Kg}$ |
| 3 | Time | Second | $\mathrm{S}$ |
| 4 | Electric Current | Ampere | $\mathrm{A}$ |
| 5 | Temperature | Kelvin | $\mathrm{K}$ |
| 6 | Luminous Intensity | Candela | $\mathrm{Cd}$ |
| 7 | Amount of Substance | $\mathrm{mole}$ | $\mathrm{mol}$ |
- $\quad$ Supplementary Units :
| S.No. | Physical Quantity | SI Unit | Symbol |
|---|---|---|---|
| 1 | Plane Angle | radian | $d\theta$ |
| 2 | Solid Angle | Steradian | $d\Omega$ |
- $\quad$ Metric Prefixes :
| S.No. | Prefix | Symbol | Value |
|---|---|---|---|
| 1 | Centi | $\mathrm{c}$ | $10^{-2}$ |
| 2 | Mili | $\mathrm{m}$ | $10^{-3}$ |
| 3 | Micro | $\mu$ | $10^{-6}$ |
| 4 | Nano | $\mathrm{n}$ | $10^{-9}$ |
| 5 | Pico | $\mathrm{p}$ | $10^{-12}$ |
| 6 | Kilo | $\mathrm{K}$ | $10^{3}$ |
| 7 | Mega | $\mathrm{M}$ | $10^{6}$ |
Unit conversion
$n_1u_1 = n_2u_2$
Dimensional equation
An equation obtained by equating a physical quantity with its dimensional formula is called the dimensional equation of the physical quantity.
Principle of homogeneity of dimensions
The magnitudes of physical quantities may be added together or subtracted from one another only if they have the same dimensions.
BETA
