A brass wire of length 2 m and radius 1 mm at 27 ° C is held taut between two rigid supports. Initially it was cooled to a temperature of -43 ° C creating a tension T in the wire. The temperature to which the wire has to be cooled in order to increase the tension in it to 1.4 T , is \ \ \ \ ° C

Physics · Thermal Properties of Matter

JEE Main 2026 — 24 January, Morning Shift — Question 37

A brass wire of length 2 m and radius 1 mm at $27^{\circ} \mathrm{C}$ is held taut between two rigid supports. Initially it was cooled to a temperature of $-43^{\circ} \mathrm{C}$ creating a tension T in the wire. The temperature to which the wire has to be cooled in order to increase the tension in it to 1.4 T , is $\_\_\_\_$ ${ }^{\circ} \mathrm{C}$

Option A:
$-86$
Option B:
$-71$
Correct
Option C:
$-65$
Option D:
$-80$

Answer: B

Step-by-step solution

$T=\alpha Y A(27-(-43)$ 1.4 T = αYA(27 - θ) using (ii)/(i)

\begin{aligned} & 1.4=\frac{27-\theta}{70} & 27-\theta=98 \therefore \theta=-71^{\circ} \mathrm{C} \end{aligned}

Answer key and solution verified before publishing.

Practise Thermal Properties of Matter

Start with this question, then two more from the same chapter — with a tutor that explains every step. Free.

Solve a similar one free

Exam: JEE Main 2026
Paper: 24 January, Morning Shift
Subject: Physics
Chapter: Thermal Properties of Matter
Topic: Thermal Expansion of Solids and its Applications