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Physics · PYQ NEET UG 2026
हिन्दीThe temperature of a metallic sphere of radius \( R \) is increased by a small amount \( \Delta T \). If the linear coefficient of thermal expansion of the metal is \( \alpha \), the approximate increase in the volume of the sphere is :
Correct answer · Option 3
\( 4\pi R^3\alpha\Delta T \)
Explanation
Volume \( V = \frac{4}{3}\pi R^3 \). Differentiating, \( \frac{\Delta V}{V} = 3\frac{\Delta R}{R} = 3\alpha\Delta T \). Thus \( \Delta V = 4\pi R^3 \alpha \Delta T \).
