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

Question

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 (A) heat flow through A and E slabs are same. (B) heat flow through slab E is maximum. (C) temperature difference across slab E is smallest. (D) heat flow through C= heat flow through B+ heat flow through D

Tardigrade Admin · Accepted Answer

Let width of each rod is d R 1=(1/8 kd ), R 2=(4/3 kd ) R 3=(1/2 kd ), R 4=(4/5 kd ) R 5=(1/24 kd )

Q. 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

heat flow through A and E slabs are same.

heat flow through slab E is maximum.

temperature difference across slab E is smallest.

heat flow through C= heat flow through B+ heat flow through D

Let width of each rod is d R1​=8kd1​,R2​=3kd4​ R3​=2kd1​,R4​=5kd4​ R5​=24kd1​

Let width of each rod is $d$
$R_{1} = \frac{1}{8 k d}, R_{2} = \frac{4}{3 k d}$
$R_{3} = \frac{1}{2 k d}, R_{4} = \frac{4}{5 k d}$
$R_{5} = \frac{1}{24 k d}$