A composite block is made of slabs A, B, C, D and E of different thermal conductivities (given in terms of a constant, K ) and sizes (given in terms of length, L ) as shown in the figure. All slabs are of same width. Heat Q flows only from left to right through the blocks. Then, in steady state

Step-by-step solution

Thermal resistance aligned & R= l K A & R_A= L (2 K)(4 L w) = 1 8 K w & (Here, w= width) & R_B= 4 L 3 K(L w) = 4 3 K w & R_C= 4 L (4 K)(2 L w) = 1 2 K w & R_D= 4 L (5 K)(L w) = 4 5 K w & R_E= L (6 K)(L w) = 1 6 K w & R_A: R_B: R_C: R_D: R_E &=15: 160: 60: 96: 12 aligned So, let us write, R_A=15 R, R_B=160 R etc and draw a simple electrical circuit as shown in figure. H= Heat current = Rate of heat flow. H_A=H_E=H [let] Option (a) is correct. In parallel, current distributes in inverse ratio of resistance. aligned &