Question 11:
easy
Five rods of same dimensions are arranged as shown in the figure. They have thermal conductivities K1, K2, K3, K4 and K5. When points A and C are maintained at different temperature, no heat flows through the central rod if

No heat flows through the central rod \(K_5\) if the system is balanced like a Wheatstone bridge. The condition for this is:
\[
\frac{K_1}{K_2} = \frac{K_3}{K_4}
\]
This ensures that the temperature difference between points B and D is zero, preventing any heat flow through \(K_5\).