Question

A wire is stretched wire is stretched so its length becomes 6 by 15 times of its original length if its original resistivity is 25 ohm find the new resistance is justification for your answer in each case​

Answer 1

Answer:

let its original length be=x

let its area be y

original resistivity=25 ohm-metre

resistivity=rho Length/area

25=rho x/y. eq1

from the question we conclude

new length of the wire=6/15 x

area =y

resistivity=rho 6/15x÷y

resistivity=6/15rho x/y

since rho x/y =25 from eq 1

hence

resistivity=6/15×25

resistivity=10 ohmmeter