1. You are to design a tungsten filament light bulb that has a power of 60W when it is connected to 120V at which condition its temperature is expected to be 1020C. You have a tungsten wire of diameter 0.05mm. Calculate the resistance that you require for the filament. Calculate the length of filament that you need.
a. Given: electrical resistivity of tungsten at 20C = 5.6 x 10 ^-8omh m
b. Temperature coefficient of resistance = 4.5 x 10^-3/C