Question

A wire of resistance $4 \, \Omega$ is stretched to twice its original length. The resistance of stretched wire would be :

• A. $16\, \Omega$
• B. $2 \,\Omega$
• C. $4 \,\Omega$
• D. $8 \,\Omega$

Answer 1

Answer: (A)

$16\, \Omega$

Answer 2

$R = \frac{\rho l }{ A} = \frac{\rho l^2}{A l} \Rightarrow \propto l^2$