Dimensions of a Physical Quantity 1
Description:
Dimensions of physical quantity is the fundamental quantities involved in the given quantity. The number of these dimensions expressed as the number how many times the fundamental quantity is multiplied i.e. all the physical quantities represented by derived units can be expressed in terms of some combination of seven fundamental or base quantities.
Fundamental quantities and their dimensions −
| Fundamental Quantity | Dimension | Unit |
|---|---|---|
| Mass | M | Kilogram(kg) |
| Length | L | Meter(m) |
| Time | T | Second(s) |
| Temperature | K | Kelvin(K) |
| Electric Current | A | Ampere(A) |
DIMENSIONAL FORMULA
The power (exponent) of base quantity that enters into the expression of a physical quantity, is called the dimensional formula of the quantity.
To make it clear, consider the physical quantity density.
Density = massvolume = ML3 = |M L-3|
Here,
massvolume = physical formula And
M L-3 = dimensional formula.
Similarly,
Dimensional formula for speed is given by −
Speed = |L T -1|
Dimensional formula for acceleration is given by −
Acceleration = |L T -2|
Dimensional formula for force is given by −
Force = |M L T -2|