Q. Five identical rods are joined as shown in figure. Point $A$ and $C$ are maintained at temperature $120℃$ and $20℃$ respectively. The temperature of junction $B$ will be
A) $100℃$
B) $80℃$
C) $70℃$
D) $0℃$
Explanation
(c) If thermal resistance of each rod is considered $R$ then, the given combination can be redrawn as follows
$(Heat\ current)_{AC} = (Heat\ current)_{AB}$
$\frac{(120 - 20)}{2R} = \frac{(120 - \theta)}{R} \Rightarrow \theta = 70℃$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.