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A composite block is made of slabs A,B,C...

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 slabs A and E is 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.

Text Solution

Verified by Experts

The correct Answer is:
A, C, D
At steardy state, heat flow through `A` and `E` are same. So option `(a)` is correct and option `(b)` is incorrect.

c. `DeltaT=HxxR` , where `H` is heat currect. ltbr. `'H'` is same for `A` and `E` but `R` is smallest. So option `(c)` is corrcet
d. `H_(B)=(DeltaT)/(R_(B)),H_(C)=(DeltaT)/(R_(C))` and `H_(D)=(DeltaT)/(R_(D))` ,
From this option if, `H_(C)=H_(B)+H_(D)`
`implies (1)/(R_(C))=(1)/(R_(B))+(1)/(R_(D))`
`implies (4K(2Lb))/(4L)=(3K(Lb))/(4L)+(5K(Lb))/(4L)`
which is true. Here `b` is the wildth of slab.
Hence option `(d)` is also correct.
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