The filament in an incandescent bulb is made from tungsten. The resistivity of tungsten is 5.6x10^-8ohm m. The radius of the tungsten wire is 0.045mm. If the bulb is to be plugged into a 120-V outlet and is to draw a current of 1.24A, how long must the wire be? In doing this question be sure to derive an algebraic expression for the length of the wire, L in terms of the voltage, V, the current, I, the radius of the wire, r, and the resistivity of the wire, p, before substituting the numerical values.