Question

Q.7 The resistance of a wire of length 300 m and cross -section area 1.0 mm square made of material of resistivity 1.0 x 10-7 Ω m​

Answer 1

Answer:

answer in attachment

Answer 2

Answer:

$\boxed{\mathfrak{Resistance \ (R) = 30 \ \Omega}}$

Given:

Length (l) = 300 m

Cross-section area (A) = 1.00 mm² = $\sf 10^{-6}$ m²

Resistivity ($\sf \rho$) = $\sf 1.0 \times 10^{-7}$ Ω-m

To Find:

Resistance (R) of the wire

Explanation:

Formula:

$\boxed{ \bold{R = \frac{\rho l}{A}}}$

Substituting values of $\sf \rho$, l & A in the equation:

$\sf \implies R = \frac{1 \times {10}^{ - 7} \times 300}{ {10}^{ - 6} }$

$\sf \implies R = 300 \times {10}^{ - 7 - ( - 6)}$

$\sf \implies R = 300 \times {10}^{ - 7 + 6}$

$\sf \implies R = 300 \times {10}^{ - 1}$

$\sf \implies R = \frac{300}{10}$

$\sf \implies R = 30 \: \Omega$

$\therefore$

Resistance (R) of the wire = 30 Ω