**"If an equation fails a dimensional consistency test it is proved wrong, but if it passes it is not proved right. A dimensionally correct equation need not be actually an exact equation, but a dimensionally wrong or inconsistent equation must be wrong." Explain.**

**"If an equation fails a dimensional consistency test it is proved wrong, but if it passes it is not proved right. A dimensionally correct equation need not be actually an exact equation, but a dimensionally wrong or inconsistent equation must be wrong." Explain.**

### Asked by Rida Mukadam | 1st May, 2015, 06:25: PM

Expert Answer:

### An equation has two sides, left hand side and right hand side. When we write an equation, the quantity on the left has to be dimensionally equal to the quantity on right. Only then that equation can be termed as correct/valid.
If, the dimensions dont match then the equation has to be incorrect. Example, writing area of square as A = side will be dimensionally incorrect as opposed to A = (side)^{2}.
However, if we write area of square as (radius)^{2}, then it would be incorrect even though it is dimensionally correct.
Hence, it is said that "If an equation fails a dimensional consistency test it is proved wrong, but if it passes it is not proved right. A dimensionally correct equation need not be actually an exact equation, but a dimensionally wrong or inconsistent equation must be wrong".

^{2}.

^{2}, then it would be incorrect even though it is dimensionally correct.

### Answered by Romal Bhansali | 4th May, 2015, 11:51: AM

## Concept Videos

- 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

#### Sign Up

#### Verify mobile number

Enter the OTP sent to your number

Change