JEE Mains · Physics · STD 11 - Transmission of heat
- JEE Mains 2026
- Easy
- MCQ
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 \( 100^{\circ}C \) and \( 40^{\circ}C \) respectively. Given the thermal conductivity of rod x is three times of that of rod y, the temperature at junction points B and E are (close to):
Pick an option to check your answer.
Answer & Solution
Correct Answer
(A) \( 89^{\circ}C \) and \( 73^{\circ}C \) respectively
Step-by-step Solution
Detailed explanation
Let \(\left[ R =\frac{\ell}{3 KA }\right]\)
\(\left[ H =\frac{100-40}{\frac{11 R }{2}}\right]\) \(\quad\) ... (1)
\(H=\frac{100-T_B}{R}\)\(\quad\) ... (2)
\(H =\frac{ T _{ E }-40}{3 R }\)\(\quad\) ... (3)
using (1) and (2)
\(120=1100-11 T_{ A }\)
\(T _{ B }=89^{\circ} C\)
using (1) and (3)
\(T _{ E }=73^{\circ} C\)
\(\left[ H =\frac{100-40}{\frac{11 R }{2}}\right]\) \(\quad\) ... (1)
\(H=\frac{100-T_B}{R}\)\(\quad\) ... (2)
\(H =\frac{ T _{ E }-40}{3 R }\)\(\quad\) ... (3)
using (1) and (2)
\(120=1100-11 T_{ A }\)
\(T _{ B }=89^{\circ} C\)
using (1) and (3)
\(T _{ E }=73^{\circ} C\)
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