You and your team are designing a small tube heater that consists of a small ceramic tube wrapped with a special heater wire composed of Nichrome. When you run an electrical current through the wire, the wire (and therefore the tube) heats up through resistive heating. Nichrome is an alloy composed of 80% nickel and 20% chromium, and has a resistivity of ρ = 1.25 × 10⁻⁶ Ω · m.

(a) What is the resistance per centimeter of 28-gauge Nichrome wire? (“28 gauge” means the wire has a diameter D = 0.320 mm)

(b) You wrap the tube with 45.0 cm of the Nichrome wire, and you want the power output of your heater to be 120 W. What current is needed?

(c) What voltage will provide the current calculated in (b)?