Q.

A wall has two layers A and B, each made of different material, “A” has thickness 10 cm, while “B” has thickness 20cm, their coefficients of conductivities are in the ratio of 3:1, a constant temperature difference of  35∘c exists across the wall, the difference of temperature across the layer “A” is

Moderate

Unlock the Full Solution and Master the Concept

Get a detailed solution and exclusive access to our masterclass to ensure you never miss a concept
By Expert Faculty of Sri Chaitanya

a

28∘c

b

14∘c

c

5∘c

d

3.5∘c

answer is 3.

(Detailed Solution Below)

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Detailed Solution

rate of transfer of heat is Qt=KA(θ1-θ2)l here k is coefficient of thermal conductivity A is area of cross section θ1-θ2 is temperature difference l is length of width  at steady state , heat transfer is constant temperature across layer  A is θ1-θ  temperature across layer  B is θ-θ2  Qt=K1A(θ1-θ)l1=K2A(θ-θ2)l2 3(θ1-θ)=12(θ-θ2)---(1) (θ1-θ2)=350C⇒θ2=θ1-35---(2) on substituting the value of θ2 from eqn(2) in eqn(1) ⇒3θ1-3θ=12θ-12θ1-35⇒6θ1-6θ=θ-θ1+35⇒7θ1-θ=35 θ1-θ=50C=temperature difference across layer A
ctaimg
Choose your Grade and Exam
edit icon

Connect with our

Expert Counsellors

access to India's best teachers with a record of producing top rankers year on year.

+91

We will send a verification code via OTP.

whats app icon