?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%.

explanation:

earth's surface is mainly heated by the absorption of infrared radiation from the sun.

evaporation occurs because molecules in liquid water are warmed ( usually by the sun) and vibrate quicker, becoming less dense and rise.

condensation occurs because molecules in water vapor are cooled and therefore vibrate more slowly thus becoming more dense and eventually fall to earth.

lines of equal barometric pressure on a weather map are called: isobars : lines of equal temp on a weather map are called: isotherms.​