If length of a conducting wire is increased by \(0.1\)%, the the resistance will increase by how much percentage?

A. \(2\)%

B. \(0.2\)%

C. \(1\)%

D. \(0.1\)%

If length of a conducting wire is increased by \(0.1\)%, the the resistance will increase by how much percentage?

A. \(2\)%

B. \(0.2\)%

C. \(1\)%

D. \(0.1\)%

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TopNewestResistance of a wire depends inversely on area of cross section and directly on length of wire. But, since volume of wire remains constant, an increase in length causes a decrease in area. Dividing the new length by new area obtained, we get the new resistance.Subtract 1 from this and then multiply by 100.This will give you the %.The calculation is not long, but it involves big numbers like 1000 and 1001(even their squares!).Use difference of 2 squares rule(HINT).Calculate, and u will get the answer very close to 0.2(actually, 0.2001). Sorry, couldn't show the calculation here! – Anibrata Bhattacharya · 1 year, 2 months ago

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– Sahba Hasan · 1 year, 2 months ago

Thanks for your help.Log in to reply

– Anibrata Bhattacharya · 1 year, 2 months ago

You are welcome!Log in to reply

Answer should be 0.2%. – Anibrata Bhattacharya · 1 year, 2 months ago

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@Calvin Lin ,@Chung Kevin ,@Nihar Mahajan , @Mehul Arora ....plz help!!! – Sahba Hasan · 1 year, 2 months ago

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Then, When a wire is stretched by x%, Then resistance will increase by 2x%. but this is applicable only x<10 (I don't know why, though)

Thus the answer should be 0.2% – Mehul Arora · 1 year, 2 months ago

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– Sahba Hasan · 1 year, 2 months ago

Thanks...you really helped me!Log in to reply

– Mehul Arora · 1 year, 2 months ago

Always welcome brother! :)Log in to reply

– Sahba Hasan · 1 year, 2 months ago

Well....i am a girl. ;)Log in to reply

– Mehul Arora · 1 year, 2 months ago

Sorry, Sister* :PLog in to reply