A 60 W lightbulb has a resistance of 240 Ω. At the operating temperature of the tungsten filament, its resistivity is approximately 5.0 x 10-7 Ω • m. If the wire used to make the filament is 0.040 mm in diameter (a typical value). As described above the length of a 60 W, 240 Ω lightbulb filament was calculated to be 60 cm.a. If the potential difference across the filament is 120 V, what is the strength of the electric field inside the filament?b. Suppose the length of the bulb’s filament were doubled without changing its diameter or the potential difference across it. What would the electric field strength be in this case?c. Remembering that the current in the filament is proportional to the electric field, what is the current in the filament following the doubling of its length?d. What is the resistance of the filament following the doubling of its length?
A 60 W lightbulb has a resistance of 240 Ω. At the operating temperature of the tungsten filament, its resistivity is approximately 5.0 x 10-7 Ω • m. If the wire used to make the filament is 0.040 mm in diameter (a typical value).
As described above the length of a 60 W, 240 Ω lightbulb filament was calculated to be 60 cm.
a. If the potential difference across the filament is 120 V, what is the strength of the electric field inside the filament?
b. Suppose the length of the bulb’s filament were doubled without changing its diameter or the potential difference across it. What would the electric field strength be in this case?
c. Remembering that the current in the filament is proportional to the electric field, what is the current in the filament following the doubling of its length?
d. What is the resistance of the filament following the doubling of its length?
Trending now
This is a popular solution!
Step by step
Solved in 2 steps with 2 images
