Tag: modes of heat transfer - conduction

Questions Related to modes of heat transfer - conduction

A cylinder of radius $R$ made of a material of thermal conductivity $K _1$ is surrounded by a cylindrical shell of inner radius $R$ and outer radius $2R$ made of a material of thermal conductivity $K _2$. The two ends of the combined system are maintained at two different temperatures. There is no loss of heat across the cylindrical surface and the system is in steady state. The effective thermal conductivity of the system is?

physics temperature and heat modes of heat transfer - conduction conduction heat and modes of heat transfer

  1. $K _1+K _2$

  2. $\dfrac{K _{1}+3K _{2}}{4}$

  3. $\dfrac{K _{1}+8K _{2}}{9}$

  4. $\dfrac{8K _{1}+K _{2}}{9}$

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Correct Option: A,C

In order that the heat flows one part of a solid to another part, what is required ?

physics temperature and heat modes of heat transfer - conduction conduction heat and modes of heat transfer

  1. uniform density

  2. temperature gradient

  3. density gradient

  4. uniform temperature

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Correct Option: B
Explanation:

As heat flows from higher temperature to lower temperature, so a temperature gradient is required.