Question

The ends of a metre stick are maintained at 100°C and 0°C. One end of a rod is maintained at 25°C. Where should its other end be touched on the metre stick so that there is no heat current in the rod in steady state?

Answer 1

Let the point to be touched be ‘B’
No heat will flow when, the temp at that point is also 25°C
i.e. Q_AB = Q_BC

So, (KA(100 - 25)/(100 - x) = (KA(25 - 0)/x

=> 75x = 2500 – 25x => 100x = 2500 => x = 25cm from the end with 0°C