Given, thermal resistance of rod CD,
RCD=10.0kW−1
Temperature of end
A,TA=200°C Temperature of end
B,TB=100°C Temperature of end
D,TD=125°C As rods are given as identical, then
RCD=RCB=10kW−1 As, C is mid-point of AB, and as we know
R ∝ length
RAC=RBC=5kW−1 Now, we know that heat current is given as
= Here, ∆T is temperature difference and R is thermal resistance.
Now, for point C, consider temperature of point C as T.
Consider at point C heat is coming in from A and going out at point B and D.
Therefore, we can write,
== ⇒=+ ⇒=, ⇒400−2T=T−125+2T−200 5T=725°C T=145°C The heat current in CD is
ICD= ===2W Thus, the value of P is 2.