A copper wire of length 10 m and radius (10-2 / √π) m has electrical resistance of 10 Ω. The current density in the wire for an electric field strength of 10( V / m ) is :

Question

A copper wire of length 10 m and radius (10-2 / √π) m has electrical resistance of 10 Ω. The current density in the wire for an electric field strength of 10( V / m ) is : (A) 105 A / m 2 (B) 104 A / m 2 (C) 106 A / m 2 (D) 10-5 A / m 2

Tardigrade Admin · Accepted Answer

Radius of wire =(10-2/√π) Cross sectional area A=π r 2=10-4 m 2 j =( i / A )=(( V / R )) ⋅ (1/ A )=( E ℓ/ RA ) R =(ρ ℓ/ A ) j =(10 × 10/10 × 10-4)=105 A / m 2 or J =σ E ⇒ (E/ρ)=( E ℓ/ RA )=(10 × 10 × π/10 × 10-4 × π) ⇒ 105 A / m 2

Q. A copper wire of length $10 m$ and radius $(1 0^{- 2} / π) m$ has electrical resistance of $10 Ω$ . The current density in the wire for an electric field strength of $10 (V / m)$ is :

$1 0^{5} A / m^{2}$

$1 0^{4} A / m^{2}$

$1 0^{6} A / m^{2}$

$1 0^{- 5} A / m^{2}$

Q. A copper wire of length 10m and radius (10−2/π​)m has electrical resistance of 10Ω. The current density in the wire for an electric field strength of 10(V/m) is :

105A/m2

104A/m2

106A/m2

10−5A/m2

Radius of wire =π​10−2​ Cross sectional area A=πr2=10−4m2 j=Ai​=(RV​)⋅A1​=RAEℓ​R=Aρℓ​ j=10×10−410×10​=105A/m2 or J=σE⇒ρE​=RAEℓ​=10×10−4×π10×10×π​ ⇒105A/m2

Q. A copper wire of length $10 m$ and radius $(1 0^{- 2} / π) m$ has electrical resistance of $10 Ω$ . The current density in the wire for an electric field strength of $10 (V / m)$ is :

$1 0^{5} A / m^{2}$

$1 0^{4} A / m^{2}$

$1 0^{6} A / m^{2}$

$1 0^{- 5} A / m^{2}$