The document describes dimensional formulae, which define physical quantities in terms of fundamental quantities, exemplified by the dimensional formula of velocity as [m0lt-1]. It also explains dimensional equations, where a physical quantity's dimension is equated with its dimensional formula, such as [v] = [m0lt-1]. Limitations of dimensional analysis include the inability to predict constants and find proportionality constants between different physical quantities.

1. Dimensional Formula and
Equations

2. Dimensional Formulae
 The formulae which are used to define a physical
quantity in terms of fundamental quantities are
called dimensional formulae
 For example dimensional formula of velocity is
[M0LT-1]
 Dimensional formulae of trigonometric,
logarithmic and exponential functions are not
defined as they are dimensionless

3. Applications of Dimensional
Formulae
 In expressing a physical quantity in terms of
fundamental quantity by raising them to certain
powers
 They are used in dimensional analysis in order to
convert units from one system to another

4. Dimensional Equations
 When we equate dimension of a physical quantity
with its dimensional formula we get a dimensional
equation
 For example, dimensional equation of velocity is
given as [v] = [M0LT-1]

5. Limitations
 We can’t predict nature of constants,
trigonometric and logarithm functions with the
help of dimensions
 We can’t find proportionality constants while
deriving relation between different physical
quantities

6. Hey Friend,
This was just a summary on Dimensional Formulae and
Dimensional Equations. For more detailed information on this
topic, please type the link given below or copy it from the
description of this PPT and open it in a new browser window.
www.askiitians.com/iit-jee-physics/general-
physics/dimensional-formulae-and-dimensional-
equations/