A cylindrical tungsten filament 15.0 cm long
A cylindrical tungsten filament 15.0 cm long with a diameter of 1.00 mm is to be used in a machine for which the temperature will range from room temperature (20°C) up to 120°C. It will carry a current of 12.5 A at all temperatures (consult Tables 25.1 and 25.2).
(a) What will be the maximum electric field in this filament, and
(b) What will be its resistance with that field?
(c) What will be the maximum potential drop over the full length of the filament?