Question

Six identical conducting rods are joined as shown in figure. Points $A$ and $D$ are maintained at temperature of ${200}^{\circ }C$ and ${20}^{\circ }C$ respectively. The temperature of junction $B$ will be :

• A. ${120}^{\circ }C$
• B. ${100}^{\circ }C$
• C. ${140}^{\circ }C$
• D. ${80}^{\circ }C$

Answer 1

The correct option is C ${140}^{\circ }C$

$k_{BC}=k$ (wheat stone bridge)

$\frac{kA(200-t_B)}{l}=\frac{kA(t_B-t_C)}{l}=\frac{kA(t_C-20)}{l}$

$t_B={140}^{\circ }C{\&t}_C={80}^{\circ }C$