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NEET2015PhysicsThermal Properties of MatterActual

A slab consists of portions of different materials of same thickness and having the conductivities K₁ and K₂ . The equivalent thermal conductivity of the slab is

Options

  1. AK₁+K₂
  2. BK₁+K₂
  3. C2 K₁ K₂ K₁+K₂
  4. DK₁ K₂ K₁+K₂

Correct answer

C. 2 K₁ K₂ K₁+K₂

Step-by-step solution

As two portions of the slab are connected in series, therefore aligned K & = x_i x_i / K₁ = d+d d K₁ + d K₂ & = 2 d d ( 1 K₁ + 1 K₂ ) = 2 K₁ K₂ K₁+K₂ aligned

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