A body with uniform cross-section has two ends with radii ( r₁ ) and ( r₂ ) with temperature ( Tᵢ ) and thermal current. What is the relationship between ( r₁ ), ( r₂ ), ( Tᵢ ), and thermal current?
a) ( r₁ = r₂ ), ( Tᵢ ) is constant
b) ( r₁ < r₂ ), ( Tᵢ ) is increasing
c) ( r₁ > r₂ ), ( Tᵢ ) is decreasing
d) ( r₁ = r₂ ), ( Tᵢ ) and thermal current are unrelated
