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Properties of Matter question

2017 · Q157
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Properties of Matter question

2017 · Q157

NEETPhysicsProperties of MatterMCQ+4 / −1
Two rods A and B of different materials are welded together as shown in figure. Their thermal conductivities are K1 and K2. The thermal conductivity of the composite will be

NEET 2017 Physics - Properties of Matter Question 81 English
  1. A
    3(K1+K2)2{{3\left( {{K_1} + {K_2}} \right)} \over 2}23(K1​+K2​)​
  2. B
    K1+K2{K_1} + {K_2}K1​+K2​
  3. C
    2(K1+K2)2\left( {{K_1} + {K_2}} \right)2(K1​+K2​)
  4. D
    K1+K22{{{K_1} + {K_2}} \over 2}2K1​+K2​​
View written solutionFree

Correct answer: D

Equivalent thermal conductivity of the composite rod in parallel combination will be,

K=K1A1+K2A2A1+A2=K1+K22K = {{{K_1}{A_1} + {K_2}{A_2}} \over {{A_1} + {A_2}}} = {{{K_1} + {K_2}} \over 2}K=A1​+A2​K1​A1​+K2​A2​​=2K1​+K2​​

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