Resistance and ohm's law with light bulb

  • Thread starter trustabdy
  • Start date
  • #1
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Homework Statement



the tungsten filament of a light bulb has a resistance of .07 ohm. if the filament is 27 cm long, what is the diameter



Homework Equations



R= p(L/A)

Area of a circular cross section = (PiD^2/4)

The Attempt at a Solution



R= p(L/A) A= (pL)/r

Homework Statement



resistance .07 ohm. lengh= .27m, resistivity= 5.6x10^-8
diameter ?

Homework Equations



A= (pL)/r
 

Answers and Replies

  • #2
19
0
can i get some help
 
  • #3
marcusl
Science Advisor
Gold Member
2,753
404
Ok, you have the right equations. From the last equation you wrote and the values you listed, what is the area A?

Once you have that, find the diameter from d=2*sqrt(A/pi).
 

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