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Two rods with identical length and cross-sectional area, having thermal conductivities K₁ and K₂, are connected side by side in parallel. What is the effective thermal conductivity of the arrangement?

1. K₁K₂/(K₁ + K₂)
2. K₁ + K₂
3. (K₁ + K₂)/2
4. √(K₁K₂)

Correct answer: (K₁ + K₂)/2

Solution

The effective thermal conductivity of two rods in parallel is the average of their conductivities, which is calculated as (K₁ + K₂)/2. This is because both rods contribute equally to the heat transfer across the same cross-sectional area.

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