Question

A wire of length I and resistance R is streched so that length is doubled and the area
of cross-section is halved How will its :
(i) resistance change ?
(ii) resistivity change ?

answer fastly​

Answer 1

Explanation:

1.Here, length is doubled and area of cross-section is halved. Thus, a wire of length l and area of cross-section A becomes a wire of length 2l and area of cross-section A/2

2.Resistivity of a substance does not depend on its length or area of cross-section. It depends on the nature of the material and temperature. Hence there is no change

Answer 2

so according to the question......

condition 1)

Data: Let new length = l' new Area =, A' and new resistance = R' Given, l' = 2l and A' = A/2 As we know R = (ρl) / A So, R' = [ρ × 2l] / (A/2) = (4 × ρl) / A = 4 × (ρ l / A ) but R = ρl/A ⇒ R' = 4 ×R Resitivity depends on the nature of material not on the length, temperature or Area of cross-section. So, resitivity will remain Constant.