Question 213: Current Electricity

Question

An aluminium wire is stretched to make its length, 0.4% larger. The percentage change in resistance is :

Accepted Answer

$$R = {{ho l} \over A}$$
Also volume will remain constant
i.e., Al = constant $$ \Rightarrow A \propto {1 \over l}$$
$$	herefore$$ $$R \propto {l^2}$$
$${{\Delta R} \over R} = 2{{\Delta l} \over l} = 0.8$$

Answer

0.4%

Answer

0.2%

Answer

0.8%

Answer

0.6%

Current Electricity

An aluminium wire is stretched to make its length, 0.4% larger. The percentage change in resistance is :

Choose the correct answer: