A 480-W heating coil designed to operate from 110 V is made of Nichrome wire 0.240 mm in diameter. (Assume ̑ = 1.50 ! 10⁻⁶ Ω · m, and α = 4.000 ! 10⁻⁴(°C)⁻¹ for Nichrome.) (a) Assuming the resistivity of the Nichrome remains constant at its 20.0°C value, find the length of wire used. (b) Now consider the variation of resistivity with temperature. What power is delivered to the coil of part (a) when it is warmed to 1 200°C?