One hundred meters of a certain type of wire has a resistance of 7.2 Ω. What is the resistance of 2.5 m of this wire?I figured it would just be a proportion so (7.2 * 2.5) / 100 = 0.18 Ω. Is this the correct approach?
yes, it's a proportion. (2.5/100)7.2 = 0.18 ohm A little more analytical approach is dimensional analysis. I sometimes get proportions backwards, but dimensional analysis prevents that. 7.2Ω/100 m = 0.072Ω/m 0.072Ω/m x 2.5m = 0.18Ω .
Resistance of a wire : R = ρ * L/A R ∝ L ( L = length of the wire) R' = L'/L * R = 2.5/100 * 7.2 = 0.18 Ω. Yup, your answer is correct
Ya!u r correct. L1=100m R1=7.2ohm.New length,(l2)=2.5m R2=7.2*2.5/100 R2=0.18ohm
