question_answer

Six identical metallic rods are joined together in a pattern as shown in the figure. Points A and D are maintained at temperatures 60°C and 240°C. The temperature of the junction B will be

A)  \[120{}^\circ C\]

B)  \[150{}^\circ C\]

C)  \[60{}^\circ C~~\]

D)  \[80{}^\circ C\]

Correct Answer: A

Solution :

 Equivalent electrical circuit will be as shown in the fig Temperature difference between A and D is \[{{180}^{o}}C\] which is equally distributed in all the rods. Therefore, temperature different between C and D will be \[{{60}^{o}}C\] or temperature of C should be \[{{180}^{o}}C\] So, the temperature at junction B \[{{180}^{o}}-\theta =\theta -{{60}^{o}}\] \[\theta ={{120}^{o}}C\]