An aluminium (resistivity ρ=2.2 × 10-8 Ω- m ) wire of a diameter 1.4 mm is used to make a 4 Ω resistor. The length of the wire is

Question

An aluminium (resistivity ρ=2.2 × 10-8 Ω- m ) wire of a diameter 1.4 mm is used to make a 4 Ω resistor. The length of the wire is (A) 220 m (B) 1000 m (C) 280 m (D) 1 m

Tardigrade Admin · Accepted Answer

Length of the wire is l =(R A/ρ) ∴ l=(4 × π ×(0.7 × 10-3)2/2.2 × 10-8) =280 m

Q. An aluminium (resistivity $ρ = 2.2 \times 1 0^{- 8} Ω - m$ ) wire of a diameter $1.4 mm$ is used to make a $4Ω$ resistor. The length of the wire is

220 m

1000 m

280 m

1 m

Length of the wire is
$l = \frac{R A}{ρ}$
$∴ l = \frac{4 \times π \times ( 0.7 \times 1 0 ^{- 3} ) ^{2}}{2.2 \times 1 0 ^{- 8}}$
$= 280 m$

Q. An aluminium (resistivity ρ=2.2×10−8Ω−m ) wire of a diameter 1.4mm is used to make a 4Ω resistor. The length of the wire is

220 m

1000 m

280 m

1 m

Length of the wire is l=ρRA​ ∴l=2.2×10−84×π×(0.7×10−3)2​ =280m

Q. An aluminium (resistivity $ρ = 2.2 \times 1 0^{- 8} Ω - m$ ) wire of a diameter $1.4 mm$ is used to make a $4Ω$ resistor. The length of the wire is

Length of the wire is
$l = \frac{R A}{ρ}$
$∴ l = \frac{4 \times π \times ( 0.7 \times 1 0 ^{- 3} ) ^{2}}{2.2 \times 1 0 ^{- 8}}$
$= 280 m$