Three rods `AB,BC` and `BD` made of the same materical and having the same area of cross section have been joined as shown is the The ends `A,C` and `D` are held at temperatures `20^(@)C` Cand `80^(@)C` respectively If each rod is of same length then find the temperature at the junction `B` of the three rods
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Explanation

Let `theta_(B)` is the temperature of the junction
In steady state `((Q)/(t))_(DB)+((Q)/(t))_(CB) = ((Q)/(t))_(BA)`
`(KA(80-theta_(B)))/(l)+(KA(80-theta_(B)))/(l)=(KA(theta_(B)-20))/(l)`
`80 -theta_(B) +80 -theta_(B) = theta_(B) - 20 rArr theta_(B) =60^(@)C`
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