?a wire is stretched 30% what is the percentage change in resistance

The percentage change in resistance of the wire is 69%.

Explanation:

Resistance of a wire can be determined by,

R = (ρl) ÷ A

Where R is its resistance, l is the length of the wire, A its cross sectional area and ρ its resistivity.

When the wire is stretched, its length and area changes but its volume and resistivity remains constant.

= 1.3l, and =

So that;

= (ρ) ÷ = (ρ × 1.3l) ÷ ()

    = (1.3lρ) ÷ ()

    = × [(ρl) ÷ A]

   = 1.69R               (∵ R = (ρl) ÷ A)

= 1.69R

Where is the new resistance, is the new length, and is the new area after stretching the wire.

The change in resistance of the wire = - R

                                      = 1.69R  - 1R

                                      = 0.69R

The percentage change in resistance = × 100

                                                               = 0.69 × 100

                                                              = 69%

The percentage change in resistance of the wire is 69%.

are there answer choices to this question? this seems like a question where you have options to choose from.

answer: b.

explanation: