Q 11-01-040NEETJEE MainMedium
The radius of a sphere is measured as $2.50\ \text{cm}$. Its volume, with due regard to significant figures, is
Answer: (B) $65.4\ \text{cm}^3$
$$V = \frac{4}{3}\pi r^3 = \frac{4}{3}\pi (2.50)^3 = 65.449\ldots\ \text{cm}^3$$
The radius has 3 significant figures ($\tfrac43$ and $\pi$ are exact), so the volume is rounded to 3 significant figures: $65.4\ \text{cm}^3$.
Solution by Sreeraj P, M.Sc Physics