Maker Pro
Maker Pro

Calculate radius of a copper wire

Mark Wambua

Oct 2, 2016
5
Joined
Oct 2, 2016
Messages
5
Calculate the radius of a copper wire dissipating heat of 100mW given the volume of the conductor is 20mm cubed and is carrying a current of 40nA. Resistivity of copper is 0.0000172.
 

Arouse1973

Adam
Dec 18, 2013
5,178
Joined
Dec 18, 2013
Messages
5,178
A please and thank you wouldnt go a miss, we are human and do this for free you know. Why do people think they can just post a thread like this and get help.
Adam
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,510
Joined
Jan 21, 2010
Messages
25,510
Why do people think they can just post a thread like this and get help.

Because we (the world generally) owe them an answer, and because being polite adds a few keystrokes and takes a few seconds that they'll never get back. The same argument applies to why they fail to read the bold print indicating what we will and will not do in this section.
 

duke37

Jan 9, 2011
5,364
Joined
Jan 9, 2011
Messages
5,364
There must be some units for resistivity. I tend to use basic S.I. units for calculations
Derive an equation for the resistance of a circular wire of nominal length and diameter, Calculate its volume.

Power dissipated is I*I/R so you can calculate the resistance and solve the equation you derived
 

Arouse1973

Adam
Dec 18, 2013
5,178
Joined
Dec 18, 2013
Messages
5,178
Because we (the world generally) owe them an answer, and because being polite adds a few keystrokes and takes a few seconds that they'll never get back. The same argument applies to why they fail to read the bold print indicating what we will and will not do in this section.

Very True Steve.
 

Mark Wambua

Oct 2, 2016
5
Joined
Oct 2, 2016
Messages
5
Peace guys!
Am so sorry for lacking courtesy
Will try to be courteous from now hence forth
Thousand apologies!
 

Mark Wambua

Oct 2, 2016
5
Joined
Oct 2, 2016
Messages
5
would someone hel[ me Calculate the radius of a copper wire dissipating heat of 100mW given the volume of the conductor is 20mm cubed and is carrying a current of 40nA. Resistivity of copper is 0.0000172 ohms mm.
 

Arouse1973

Adam
Dec 18, 2013
5,178
Joined
Dec 18, 2013
Messages
5,178
Are you sure it's nA and not mA. That's going to need to be very large in resistance. Also as this is homework, how far have you got yourself. Can you show us your work so far?
Adam
 

Mark Wambua

Oct 2, 2016
5
Joined
Oct 2, 2016
Messages
5
Electronics.PNG
I have done a bit and got stuck. It is nA Adam. See attached screen shot.
 
Last edited:

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,510
Joined
Jan 21, 2010
Messages
25,510
Currently you've gone one step too far. You want the equation describing the resistance in terms of the wire's diameter and length.

Also, given the power and current, can you calculate resistance?

Putting these together you'll have an equation with 2 unknowns.

Do you have sufficient information to state either diameter or length in terms of the other?
 
Top