1. A steel bar, 20 mm in diameter and 200 mm long, with an emissivity of 0.9, is removed from a furnace at 455°C and suddenly submerged horizontally in a water bath under atmospheric pressure. Estimate the initial heat transfer rate from the bar.
2. Electrical current passes through a horizontal, 2-mm- diameter conductor of emissivity 0.5 when immersed in water under atmospheric pressure.
(a) Estimate the power dissipation per unit length of the conductor required to maintain the surface temperature at 555°C.
(b) For conductor diameters of 1.5, 2.0, and 2.5 mm, compute and plot the power dissipation per unit length as a function of surface temperature for 250 Ts 650°C. On a separate figure, plot the percentage contribution of radiation as a function of Ts.