a copper wire has cross sectional area of 4*10^-8 ohm meter. Calculate its length to make its resistance 10 ohm. How much does R change if the diameter of the wire is doubled?
Answers
Answered by
1
Wire A.
Length = l.
Radius =r.
Area =pie r2.
R1= rho x l /pie r2.
Wire B.
Length = 2l.
Radius = 2r.
Area = pie 4r2.
R2= rho x 2l/pie 4r2=rho x l /pie x 2r2.
total resistance.
1/Rp= 1/R1+1/R2.= pie r2/rho x l+2 pie r2/ rho x l.=3 pie r2/rho x l.
Rp= rho x l/ 3 pie x r2.
ratio = Rp/ R1= rho /3 pie r2divided by rho x l / pie x r2.
Rp / R1= 1 : 3.
Hope it helps you.
Answered by
3
Answer:
Given,
R= 10Ω
A= 10×10 ^−8 m ^2
ρ=1.6×10 ^−8Ω/m
We know that,
R =ρ A/l
l= RA/ρ
10×10×10 ^−8
=___________
1.6×10 ^−8
l =62.5m
The length of wire copper wire is 62.5m.
Similar questions