- #1
rinarez7
- 27
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]1. A 1.3 cm length of tungsten filament in a small lightbulb has a resistance of 0.032 ohms. Find its diameter.
Given: Length= 1.3 cm= .013m
R= 0.032 ohms
resistivity= 5.6e-8 ohms*meter
2.
A= pi (r^2)
R= resistivity (Length/ Area)
R= resistivity ( Length/ pi* (r^2) )
.032 ohms= (5.6e-8 ohms*meter) * (.o13m/ (pi* (r^2)) )
.032 (pi) (r^2) = 7.28e-10
.100530965 (r^2) = 7.28e-10
r= 8.509e-5
diameter= 2r= 1.701e-4m
It asks for the answer in mm, so I divided my answer by 1000= 1.7 e-7 mm, but it's not correct = (
What am I missing?
Thanks in advance!
Given: Length= 1.3 cm= .013m
R= 0.032 ohms
resistivity= 5.6e-8 ohms*meter
2.
A= pi (r^2)
R= resistivity (Length/ Area)
The Attempt at a Solution
R= resistivity ( Length/ pi* (r^2) )
.032 ohms= (5.6e-8 ohms*meter) * (.o13m/ (pi* (r^2)) )
.032 (pi) (r^2) = 7.28e-10
.100530965 (r^2) = 7.28e-10
r= 8.509e-5
diameter= 2r= 1.701e-4m
It asks for the answer in mm, so I divided my answer by 1000= 1.7 e-7 mm, but it's not correct = (
What am I missing?
Thanks in advance!
And you're welcome!
