Question

calculate d resistivity of d material of a wire 1 m long,0.4 mm in diameter and having a resistance of 2 ohm.???

Answer 1

length of wire, l = 1m

diameter of cross sectional area of wire , d = 0.4mm = 4 × 10^-4 m

so, cross sectional area of wire, A = πd²/4 = π(4 × 10^-4)²/4 = 4π × 10^-8 m²

resistance of wire, R = 2ohm.

we know,

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

where $\rho$ is resistivity or specific resistance of material of the wire.

or, 2 = $\rho$ × 1/{4π × 10^-8}

or, 2 × 4π × 10^-8 = $\rho$.

or, $\rho$ = 8π × 10^-8 ohm.m

= 25.12 × 10^-8 ohm.m

= 2.512 × 10^-7 ohm.m

hence, resistivity of material is 2.512 × 10^-7 ohm.m

Answer 2

Answer:

The answer of your question is given above.