To calculate the length of the wire, we use the formula for resistance: \(R = \frac{\rho \cdot L}{A}\) Where: - \( R \) is the resistance (21 \Omega), - \( \rho \) is the resistivity (\( 1.1 \times 10^{-8} \, \Omega \, m \)), - \( L \) is the length of the wire, - \( A \) is the cross-sectional area (\( 2\pi \times 10^{-8} \, m^2 \)). Rearranging the formula to solve for length \( L \): \(L = \frac{R \cdot A}{\rho}\) Substituting the known values, we first calculate the area \( A \): \(A = 2\pi \times 10^{-8} \, m^2 = 2 \times \frac{22}{7} \times 10^{-8} \approx 8.0 \times 10^{-8} \, m^2\) Now substitute into the length formula: \(L = \frac{21 \, \Omega \cdot 8.0 \times 10^{-8} \, m^2}{1.1 \times 10^{-8} \, \Omega \, m}\) Calculating: \(L = \frac{21 \cdot 8.0}{1.1}\)m \(L = \frac{168}{1.1} \, m \approx 120\)m