Question

A common flashlight bulb is rated at 0.90 A and 2.90 V (the values of current and voltage under operating conditions). If the resistance of the bulb's tunesien fila- ment at room temperature (20.0YC) is 1.10 22. estimate the temperature of the tungsten filament when the balb is turned on.

use kirchoffs rule if applicable

A common flashlight bulb is rated at 0.300 A and 2.90 V (the values of current and voltage under operating conditions). if the resistance of the bulbs tungsten filament at room temperature (20.0 degrees C) is 1.10( ), estimate the temperature of the tungsten Filament when the bulb is turned on.

Answer 1

is R = 2.90 0.3 now Ref - resistance at 700 m resistance of the filament at operating point 29 we know, Ro Roy [+ a(T-Toy) where R = resistance at temp T temp (20%) = 1.102 x= temp Coefficient of tungsten = 0.0045 per oc T= we need to measure 29 - - [1+ 0.0045 (T-20)] 0.0045 (T-20) (T-20) = or (T-20) = 1730.64 * T = 1750-64°C Т. = 20°C res 02 29 1 + 3-3 07 0.45x102 25.7 3.3 257 33