NEET Thermal Expansion MCQs & PYQs

Thick glass is a poor thermal conductor. When hot water is poured, the inner surface expands rapidly due to heating, while the outer surface remains cold and resists expansion.

This differential thermal expansion creates significant stress, causing the glass to crack. Both A and R are true, and R is the correct explanation for A.

The standard linear expansion formula \(ell = \ell_0 (1 + \alpha \Delta T)\text{ is an approximation valid for small }\alpha \Delta T\), derived from the exponential form \(ell = \ell_0 \text{e}^{\alpha \Delta T}\). If \(alpha \Delta T\) is large, this approximation fails. Both (A) and (R) are true, and (R) correctly explains (A).

Coefficient of volume expansion is three times the coefficient of linear expansion for an isotropic solid, i.e., \(\gamma = 3\alpha\).