Question

A conductor of length 80 cm has a resistance of 4.80 Ω, calculate the resistance of similar conductor of length 640 cm.

Answer 1

Since the conductors are similar, they are made of the same material and have the same area of cross-section. Therefore, resistance is directly proportional to length.

R ∝ l

So, `R_1/R_2 = l_1/l_2`

Here, R₁ = 4.80 Ω, l₁ = 80 cm, l₂ = 640 cm

`R_2 = R_1 xx l_2/l_1`

= `4.80 xx 640/80`

= 4.80 × 8

= 38.4 Ω

Thus, the resistance of the conductor of length 640 cm is 38.4 Ω.