1. The problem statement, all variables and given/known data A 2.5 cm length of tungsten filament in a small lightbulb has a resistance of 0.041 . Find its diameter. (The resistivity is 5.6 × 10−8 · m). Answer in units of mm. 2. Relevant equations R=p(L/pi*r^2) 3. The attempt at a solution i have reworked the equation to the square root of pL/R*pi equals r and then multiplied that answer by 2 which nds u being 2.0856e-4 but it is not right??