Two parallel wires 2 m apart carry currents of 2 A and 5 A respectively in same direction, the force per unit length acting between these two wires is

Question

Two parallel wires 2 m apart carry currents of 2 A and 5 A respectively in same direction, the force per unit length acting between these two wires is (A) 2 × 10-6N m-1 (B) 3 × 10-6 N m-1 (C) 1 × 106 N m-1 (D) 4 × 10-6 N m-1

Tardigrade Admin · Accepted Answer

Given, I1=2A, I2=5A, r=2 m ∴ f=(μ0/4π)(2I1I2/r)=10-7×(2×2×5/2) =1×10-6 N m-1

Q. Two parallel wires $2 m$ apart carry currents of $2 A$ and $5 A$ respectively in same direction, the force per unit length acting between these two wires is

$2 \times 1 0^{- 6} N m^{- 1}$

$3 \times 1 0^{- 6} N m^{- 1}$

$1 \times 1 0^{6} N m^{- 1}$

$4 \times 1 0^{- 6} N m^{- 1}$

Given, $I_{1} = 2 A$ ,
$I_{2} = 5 A$ ,
$r = 2 m$
$∴ f = \frac{μ _{0}}{4 π} \frac{2 I _{1} I _{2}}{r} = 1 0^{- 7} \times \frac{2 \times 2 \times 5}{2}$
$= 1 \times 1 0^{- 6} N m^{- 1}$

Q. Two parallel wires 2m apart carry currents of 2A and 5A respectively in same direction, the force per unit length acting between these two wires is

2×10−6Nm−1

3×10−6Nm−1

1×106Nm−1

4×10−6Nm−1