"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".

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