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Physics - Heat & Thermo Question with Solution | TestHub

PhysicsHeat & ThermoThermal ExpansionMedium2 minQB

PhysicsMediumsingle choice

A metal wire is clamped between two vertical walls. At $2 0^{\circ} C$ the unstrained length of the wire is exactly equal to the separation between the walls. If the temperature of the wire is decreased, which graph shows elastic energy density $u$ against temperature $T$ ?

Options:

Answer:

Solution:

Cooling creates tensile strain $α (20 - T)$
Elastic energy density is
$u = \frac{1}{2} Y α^{2} (20 - T)^{2}$
It is zero at $20^{\circ} C$ and rises quadratically on cooling.
This is graph B.

Stream:JEESubject:PhysicsTopic:Heat & ThermoSubtopic:Thermal Expansion

⏱ 2mℹ️ Source: QB

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