Question 182: Units , Dimensions and Error Analysis

Question

A copper wire is stretched to make it 0.5% longer. The percentage change in its electrical resistance if its volume remains unchanged is :

Accepted Answer

We know,
$$R = {{ho l} \over A}$$
and Volume (V) = A$$l$$
$$ \Rightarrow $$   A $$=$$ $${V \over l}$$
$$ 	herefore $$   $$R = {{ho {l^2}} \over v}$$
$$ 	herefore $$   $${{\Delta R} \over R} = 2{{\Delta l} \over l}$$
$$=$$   2 $$ 	imes $$ 0.5
$$=$$ 1%

Answer

2.0 %

Answer

2.5 %

Answer

1.0 %

Answer

0.5 %

Units , Dimensions and Error Analysis

A copper wire is stretched to make it 0.5% longer. The percentage change in its electrical resistance if its volume remains unchanged is :

Choose the correct answer: