If a copper wire is stretched to make its radius decrease by 0.1 %, then the percentage increase in resistance is nearly

Question

If a copper wire is stretched to make its radius decrease by 0.1 %, then the percentage increase in resistance is nearly (A) 0.1 % (B) 0.8 % (C) 0.4 % (D) 0.2 %

Tardigrade Admin · Accepted Answer

For x % decrease in radius, increase in resistance is 4 × % ⇒ 0.4 %

Q. If a copper wire is stretched to make its radius decrease by $0.1%$ , then the percentage increase in resistance is nearly

$0.1%$

$0.8%$

$0.4%$

$0.2%$

For $x %$ decrease in radius, increase in resistance is $4 \times %$
$\Rightarrow 0.4%$

Q. If a copper wire is stretched to make its radius decrease by 0.1%, then the percentage increase in resistance is nearly

0.1%

0.8%

0.4%

0.2%