Question

Explain the use of dimensional analysis to check the correctness of a physical equation.

Answer 1

Correctness of a physical equation by dimensional analysis:

1. A physical equation is correct only if the dimensions of all the terms on both sides of that equations are the same.

2. For example, consider the equation of motion.

v = u + at ……………. (1)

3. Writing the dimensional formula of every term, we get

Dimensions of LH.S. [v] [L¹M⁰T^-1],

Dimensions of R.H.S. = [u] + [at]

4. As dimensions of both side of equation is same, physical equation is dimensionally correct.