How can we find the dimensions of any physical quantity in the simplest way????? Please tell me as soon as possible.
Asked by Pragnya Kar | 29th Sep, 2014, 11:18: PM
The seven fundamental or base quantities chosen in SI units are the seven dimensions. They are denoted within square brackets[ ] .
Length is represented by [L], mass by [M] time by [T] ,electric current by [A] temperature by [K], luminous intensity by [Cd]
and amount of substance by [mol].
The dimensions of a physical quantity are the powers or exponents to which the units of base quantities are raised to represent a derived unit of that quantity.
All physical quantities can be represented in terms of the dimensions of length[L] , mass[M], and time[T]
Example: Area = length × breadth = L× L
Dimensional formula = [L]2
Thus to represent area we have to raise [L] to the power 2. Therefore Area is said to have two dimensions in length . As unit of mass and time are not required in representing area , we can write the dimensional formula of area as: [M0L2T0] and hence we say that area has zero dimension in mass and time in addition to 2 dimensions in length.
Similarly Velocity =displacement / Time
=[L] / [T]
Velocity =[LT-1] =[M0L1T-1]. This is the dimensional formula of velocity
The dimensions of velocity are : zero in mass. +1 in length and -1 in time.
To find the dimensions :
First the relation of the physical quantity with respect to other quantities have to be known, like density = mass/ volume. And then its written in terms of the dimensions of the fundamental quantities .In such a way you can find the dimensions of any physical quantity.
Answered by Jyothi Nair | 30th Sep, 2014, 10:50: AM
- For class 12 physics cbse board will they ask us dimensional formula for anything?will there be questions expected as to write the dimensional formulas?
- if the unit of length and mass be doubled then the numerical value of w. r. t present value of universal gravitational constant will become
- check the dimensional accuracy of n=1/2L*rootT/M
- plzz solve this my que
- Check the correctness of the equation, When the rate of flow of a liquid having a coefficient of viscosity ‘η’ through a capillary tube of length ‘l’ and radius ‘a’ under true pressure head ‘p’ is given by 𝑑𝑉 ÷ 𝑑t = 𝜋𝑝𝑎^4 ÷ 8lη
- Please undoubt the question . Image is attached.
- if area (a) velocity (v) and density(p)are base units,then whats the dimensinal formula of force represented as
- Q) How many significant Figures are there in ₹1000 and 1000pens? Please answer along with concept.
- using dimensional analysis, the accuracy of relation 𝒗 = 𝒌𝒏 𝒓𝒅 , v is Velocity, k is constant, n is coefficient of viscosity [ML-1 T -1 ] , r is radius and d is density.
- what is significance of uncertaitanity principle
Kindly Sign up for a personalised experience
- Ask Study Doubts
- Sample Papers
- Past Year Papers
- Textbook Solutions
Verify mobile number
Enter the OTP sent to your number