A composite block is made of slabs , , , and of different thermal conductivities (given in terms of a constant ) and sizes (given in terms of length, ) as shown in the figure. All slabs are of same width. Heat flows only from left to right through the blocks. Then in steady state
Answers: A. heat flow through A and E slabs are same. · C. temperature difference across slab E is smallest. · D. heat flow through heat flow through B + heat flow through D.
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Written solution
Step 1: Identify the slab connections.
Slabs B, C, and D are in parallel, while A and E are in series with this combination.
Step 2: Determine the heat flow rates.
The heat flow rate through series components is equal, while parallel heat flows divide by conductivity.
Step 3: Determine the temperature differences.
The temperature difference across each section depends on its thermal resistance.
Answer: In steady state, the heat flow rate through A is equal to that through E (), and the temperature difference across E is minimum.