Question

A wire of resistance 1000 and length in increased to twice its original length. Calculate its new resistance

Answer 1

Answer:

4000 Ω

Explanation:

We know R = ρ*l/A

Here l = length, A = area of cross section, and ρ = resistivity of material.

Given, ρ*l/A = 1000 Ω

If the length is doubled, new length = 2l

Now, the volume of wire = constant.

Let the new cross sectional area be x.

So, Al = x*2l  => x = A/2

So, new resistance = ρ*2l/(A/2) = 4 * ρ*l/A = 4*1000 = 4000 Ω