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A large cylindrical rod of length L is made by joining two identical rods of copper and steel of length ( L 2 ) each. The rods are completely…

JEE Main 2012 — Physics Thermodynamics

2012mcqmedium

A large cylindrical rod of length LLL is made by joining two identical rods of copper and steel of length (L2)\left(\frac{L}{2}\right)(2L​) each. The rods are completely insulated from the surroundings. If the free end of copper rod is maintained at 100∘C100^{\circ} \mathrm{C}100∘C and that of steel at 0∘C0^{\circ} \mathrm{C}0∘C then the temperature of junction is (Thermal conductivity of copper is 9 times that of steel)

Official previous-year question

Held on 19 May 2012 · Verified 6 Jul 2026.

Options

  1. A

    90∘C90^{\circ} \mathrm{C}90∘C

  2. B

    50∘C50^{\circ} \mathrm{C}50∘C

  3. C

    10∘C10^{\circ} \mathrm{C}10∘C

  4. D

    67∘C67^{\circ} \mathrm{C}67∘C

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