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JEE Main 202622 JanuaryMorning Shift

Exam: JEE Main
Year: 2026
Date: 22 January
Shift: Morning Shift
Subject: Physics
Chapter: Thermal Properties of Matter

JEE Main 2026 · 22 January · Morning Shift · Physics · Thermal Properties of Matter

Rods x and y of equal dimensions but of different materials are...

Rods

x

and

y

of equal dimensions but of different materials are joined as shown in figure. Temperatures of end points

A

and

F

are maintained at

100^{\circ} \mathrm{C}

and

40^{\circ} \mathrm{C}

respectively. Given the thermal conductivity of

\operatorname{rod} x

is three times of that of

\operatorname{rod} y

, the temperature at junction points

B

and

E

are (close to):
Rods x and y of equal dimensions but of different materials are joined as shown in figure. Temperatures of end points A

Rods x and y of equal dimensions but of different materials are joined as shown in figure. Temperatures of end points A

Options

A $80^{\circ} \mathrm{C}$ and $70^{\circ} \mathrm{C}$ respectively
B $80^{\circ} \mathrm{C}$ and $60^{\circ} \mathrm{C}$ respectively
C $60^{\circ} \mathrm{C}$ and $45^{\circ} \mathrm{C}$ respectively
D $89^{\circ} \mathrm{C}$ and $73^{\circ} \mathrm{C}$ respectively

Correct answer

D. $89^{\circ} \mathrm{C}$ and $73^{\circ} \mathrm{C}$ respectively

Step-by-step solution

Let

\left[ R = \dfrac{\ell}{3KA} \right]

Rods x and y of equal dimensions but of different materials are joined as shown in figure. Temperatures of end points A

\left[ H = \dfrac{100 - 40}{\dfrac{11R}{2}} \right]

...(1)

H = \dfrac{100 - T_B}{R}

.....(2)

H = \dfrac{T_E - 40}{3R}

.....(3)
using (1) and (2)

120 = 1100 - 11T_A

T_B = 89°C

using (1) and (3)

T_E = 73°C

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