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
PYQ-2023-Q1 $$n_1u_1 = n_2u_2$$
Dimensional equation
PYQ-2023-Units-and-Dimensions-Q1
PYQ-2023-Units-and-Dimensions-Q2
PYQ-2023-Units-and-Dimensions-Q3
PYQ-2023-Units-and-Dimensions-Q4
PYQ-2023-Units-and-Dimensions-Q5
PYQ-2023-Units-and-Dimensions-Q8
PYQ-2023-Units-and-Dimensions-Q9
PYQ-2023-Units-and-Dimensions-Q10
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
PYQ-2023-Units-and-Dimensions-Q6, PYQ-2023-Units-and-Dimensions-Q7, PYQ-2023-Units-and-Dimensions-Q11, PYQ-2023-Units-and-Dimensions-Q12
The magnitudes of physical quantities may be added together or subtracted from one another only if they have the same dimensions.
