The soldering iron tip in Problem 1.50 becomes oxidized with age and its gray-body emittance increases to 0.8. Assuming that the surroundings are at 20?C determine the power requirement for the soldering iron. Problem 1.50:Determine the power requirement of a soldering iron in which the tip is maintained at 400?C. The tip is a cylinder 3 mm in diameter and 10 mm long. Surrounding air temperature is 20?C and the average convective heat transfer coefficient over the tip is 20 W/(m2 K). Initially, the tip is highly polished giving it a very low emittance.GIVENSoldering iron tipDiameter (D) = 3 mm = 0.003 mLength (D) = 10 mm = 0.01 mTemperature of the tip (Tt) = 400?CTemperature of the surrounding air (T??) = 20?CAverage convective heat transfer coefficient ( hc ) = 20 W/(m2 K)Emittance of the tip (ε) = 0.8ASSUMPTIONSSteady state conditions existAll power used by soldering iron is used to heat the tipThe surroundings of the soldering iron behave as a blackbody enclosureThe end of the tip isflat

T. = 20C T= 400C D-0.003 m L- 0.01 m Soldering Iron