Question

if the length and area of cross section of a copper wire is changed guess the changes in the specific Resistance of copper wire​

Answer 1

Answer:

Resistance= Resistivity x length/area

When the wire is stretched to double the length , the area of cross section gets reduced to half.

So

New Resistance = Resistivity x 2length/area/2

I.e,

New resistance = (Resistivity x length/area)x4

i.e, New resistance = Resistance x 4

So when the wire is stretched, the resistance multiplies by four times.

Hope you understood. Keep exploring.

Edit: Why does area gets halved when length is doubled?

Volume of the wire remains constant before and after the stretching.

Volume = Cross sectional area x length

Explanation:

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