Question

The figure shows the face and interface temperature of a composite slab containing of four layers of three materials having indentical thickness. Under steady state condition, find the value of temperture `theta`.

Answer 1

In steady state
Heat current will be same
Hence
`i=((dH)/(dt))_(4k)=((dH)/(dt))_(2k)=((dH)/(dt))_(k)`
`[(dH)/(dt)=(-kADeltaT)/(i)]`
`implies ((dH)/(dt))_(4k)=((4k)A(40-35))/(i)`.......`(i)`
`((dH)/(dt))_(k)=(k(25-theta))/(i)`..........`(ii)`
`(i)=(ii)` gives on solving
`theta=5^(@)`