It is proposed to coat a 1 mm diameter wire with enamel paint (k = 0.1 W/mK) to increase heat transfer with air. If the air side heat transfer coefficient is 100 W/m^2.K, the optimum thickness of enamel paint should be ______ A. 0.25 mm B. 0.5 mm C. 1 mm D. 2 mm
Ans:
One should not get confused between the critical thickness of insulation and the critical radius of insulation.