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Que. The thermal resistance for heat conduction through a spherical wall is
a. (r₂-r₁)/2πkr₁r₂
b. (r₂-r₁)/3πkr₁r₂
c. (r₂-r₁)/πkr₁r₂
d. (r₂-r₁)/4πkr₁r₂
Correct Answer:(r₂-r₁)/4πkr₁r₂
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