QJEEM20Phf1df: JEE Main 2020 Physics - Class 11 JEEM20Phf1df Solution: Three rods of identical cross-section and lengths are made of…
Three rods of identical cross-section and lengths are made of three different materials of thermal conductivity K1 , K2 and K3 , respecrtively. They are joined together at their ends to make a long rod (see figure). One end of the long rod is maintained at 100oC and the other at 0oC (see figure). If the joints of the rod are at 70oC and 20oC in steady state and there is no loss of energy from the surface of the rod, the correct relationship between K1 , K2 and K3 is :
Multiple Choice Options
AK1 : K3 = 2 : 3, K2 : K3 = 2 : 5
BK1 < K2 < K3
CK1 : K2 = 5 : 2, K1 : K3 = 3 : 5
DK1 > K2 > K3
Step-by-Step Verified Solution
All three rods have same length() and area of cross-section(A).
They are in series combination so heat current is same for all rods.
