Department of Pre-University Education, KarnatakaPUC Karnataka Science Class 11

# Let X and a Stand for Distance. is ∫ D X √ a 2 − X 2 = 1 a Sin − 1 a X Dimensionally Correct? - Physics

Sum

Let x and a stand for distance. Is
$\int\frac{dx}{\sqrt{a^2 - x^2}} = \frac{1}{a} \sin^{- 1} \frac{a}{x}$ dimensionally correct?

#### Solution

Dimension of the left side of the equation= ${\left[ \int\frac{dx}{\sqrt{\left( a^2 - x^2 \right)}} \right]} = {\left[ \int\frac{L}{\sqrt{\left( L^2 - L^2 \right)}} \right]} = \left[ L^0 \right] \text{Dimension of the right side of the equation} = \left[ \left( \frac{1}{a} \right) \sin^{- 1} \left( \frac{a}{x} \right) \right] = \left( L^{- 1} \right)$
So,
${\left[ \int\frac{dx}{\sqrt{\left( a^2 - x^2 \right)}} \right]} \neq \left[ \left( \frac{1}{a} \right) \sin^{- 1} \left( \frac{a}{x} \right) \right]$

Since the dimensions on both sides are not the same, the equation is dimensionally incorrect.

Concept: What is Physics?
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#### APPEARS IN

HC Verma Class 11, Class 12 Concepts of Physics Vol. 1
Chapter 1 Introduction to Physics
Exercise | Q 19 | Page 10
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