Question

The resistance of 1 m of nichrome wire is $6\Omega$, Calculate its resistance if its length is 70 cm

• A. $4.2\Omega$
• B. $8.4\Omega$
• C. $3.6\Omega$
• D. $6.3\Omega$

Answer 1

The correct option is A $4.2\Omega$

$R=\rho \frac{L}{A}$

$⟹R\propto L$

$⟹\frac{R_2}{R_1}=\frac{L_2}{L_1}$

$⟹\frac{R_2}{6}=\frac{0.7}{1}$

$⟹R_2=4.2\Omega$

Answer-(A)