A cylinder of radius r and made of material of thermal conductivity k 1 is surrounded by a cylindrical shell of inner radius r and outer radius 2r. This outer shell is made of a material of thermal conductivity k 2. Net conductivity would be

A cylinder of radius r and made of material of thermal conductivity k

1.	A cylinder of radius r and made of material of thermal conductivity k ₁ is surrounded by a cylindrical shell of inner radius r and outer radius 2r. This outer shell is made of a material of thermal conductivity k ₂. Net conductivity would be
A.	k <sub>1</sub> + 3 k <sub>2</sub>/4
B.	k <sub>1</sub> + k <sub>2</sub>/4
C.	k <sub>1</sub> + 3k <sub>2</sub>
D.	k <sub>1</sub> + k <sub>2</sub>
Answer» B. k <sub>1</sub> + k <sub>2</sub>/4

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A cylinder of radius r and made of material of thermal conductivity k <sub>1</sub> is surrounded by a cylindrical shell of inner radius r and outer radius 2r. This outer shell is made of a material of thermal conductivity k <sub>2</sub>. Net conductivity would be

A cylinder of radius r and made of material of thermal conductivity k 1 is surrounded by a cylindrical shell of inner radius r and outer radius 2r. This outer shell is made of a material of thermal conductivity k 2. Net conductivity would be

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A cylinder of radius r and made of material of thermal conductivity k ₁ is surrounded by a cylindrical shell of inner radius r and outer radius 2r. This outer shell is made of a material of thermal conductivity k ₂. Net conductivity would be