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NEET2017PhysicsThermal Properties of MatterActual

Two rods A and B of different materials are welded together as shown in figure. Their thermal conductivities are K 1 and K 2 . The thermal conductivity of the composite rod will be

Options

  1. AK 1 + K 2 2
  2. B3 K 1 + K 2 2
  3. CK 1 + K 2
  4. D2 K 1 + K 2

Correct answer

A. K 1 + K 2 2

Step-by-step solution

Thermal current H = H 1 + H 2 = K 1 A T 1 - T 2 d + K 2 A T 1 - T 2 d K E Q 2 A T 1 - T 2 d = A T 1 - T 2 d K 1 + K 2 K E Q = K 1 + K 2 2

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