Two materials having coefficients of thermal conductivity 3 K and K and thickness d and 3 d respectively,…

Two materials having coefficients of thermal conductivity 3K and K and thickness d and 3d respectively, are joined to form a slab as shown in the figure. The temperatures of the outer surfaces are θ2 and θ1 respectively, θ2>θ1. The temperature at the interface is

  1. θ2+θ12
  2. θ16+5θ26
  3. θ13+2θ23
  4. θ110+9θ210

Solution



Let the temperature of the junction T °C .

Rate of heat flow in Rod 1 = rate of heat flow in Rod 2

3kAdθ2-T=kA3dT-θ1

9θ2-T=T-θ1

10T=9θ2+θ1

T=9θ2+θ110=θ110+9θ210

Asked in: JEE Main 2019 (09 Apr Shift 2)

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