Two identical metal of thermal conductivities K₁ and K₂ respectively are connected in series. The effective thermal conductivity of the combination is:

Option 1 -

(K₁ + K₂) / K₁K₂

Option 2 -

(K₁ + K₂) / 2K₁K₂

Option 3 -

2K₁K₂ / (K₁ + K₂)

Option 4 -

K₁K₂ / (K₁ + K₂)

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1 Answer

Answered by

Vishal Baghel | Contributor-Level 10

a month ago

Correct Option - 3

Detailed Solution:

R_eq = R? + R?

L_total / (K_eq * A) = L? / (K? A) + L? / (K? A)
Assuming L? = L? = l, L_total = 2l

2l / (K_eq * A) = l/ (K? A) + l/ (K? A)

2/K_eq = 1/K? + 1/K? = (K? + K? )/ (K? )

K_eq = 2K? K? / (K? + K? )

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