Resistance and ohm's law with light bulb

  • Thread starter trustabdy
  • Start date
  • #1
19
0

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
2,792
451
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).
 

Related Threads on Resistance and ohm's law with light bulb

  • Last Post
Replies
4
Views
4K
  • Last Post
Replies
1
Views
4K
  • Last Post
Replies
14
Views
4K
  • Last Post
Replies
1
Views
4K
  • Last Post
Replies
4
Views
6K
  • Last Post
Replies
6
Views
1K
  • Last Post
Replies
3
Views
2K
  • Last Post
Replies
5
Views
863
  • Last Post
Replies
2
Views
8K
Replies
11
Views
11K
Top