2391 Question

[DoBBY]

Q, A conductor of length 50m has a resisitance of 2.3m ohms/m. A second identical conductor is to be installed in parrallelwith this conductor. Determine the total resisitance of these 2 conductors when connected in parallel.

Would this be the correct solution to the answer;

Formula = (mohms/m + m/ohms/m) x L / 1000

= (2.3 + 2.3) x50 / 1000 = 0.23 ohms

Any feedback would be appreciated.

DoBBY

 

[Denatone]

Resistance of one would be R=50m x 2.3 mohms/m = 0.115mohms
Resistance in parallel 1/Rtotal = 1/R1 +1/R2
As they're identical R1=R2=R
so 1/Rtotal = 1/R +1/R = 2/R
RTotal = R/2
Rtotal = 0.115mohms/2 = 0.0575mohms
You've effectively doubled the cross sectional area of conductor and so halved the resistance

 

[CRAGS]

This is one question that I quickly brushed past.