Question

a electric wire of resistance 10ohm is stretched to increase its lenght by 2 times .by what % will the resistance by increased ?
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Answer 1

Answer:

Let us check the equation. Resistance= resistivity*length/area

For a wire that is stretched/ melted and reformed/ made into another shape, volume is constant.

Therefore, we change the above equation to include V and then find the relation between resistance and length.

Multiplying both sides with length, we get resistance= resistivity*(length)*2/ volume

Now resistance is proportional to the square of length.

If length increases by two times, resistance increases by 4 times. New resistance =40 ohm

% increase in resistance= change in resistance*100/initial resistance

= 30*100/10= 300 %

Explanation:

Answer 2

Answer:

14.4ohm

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