Two parallel wires 1 m apart carry currents of 1 A and 3 A respectively in opposite directions. The force per unit length acting between these two wires is

Question

Two parallel wires 1 m apart carry currents of 1 A and 3 A respectively in opposite directions. The force per unit length acting between these two wires is (A) 6×10-7 Nm-1 repulsive (B) 6×10-7 Nm-1 attractive (C) 6×10-5 Nm-1 repulsive (D) 6×10-5 Nm-1 attractive

Tardigrade Admin · Accepted Answer

Key concept As we know that, force between two parallel current carrying conductors in the same direction attract each other and those carrying currents in the opposite direction repel each other.
Given,

I_{1} = 1 A

I_{2} = 3 A

d = 1 m

We know that, force per unit length acting between two wires,

f = \frac{μ _{0} I _{1} I _{2}}{2 π d}

f = \frac{2 \times 1 0 ^{- 7} \times 1 \times 3}{1}

f = 6 \times 1 0^{- 7} N m^{- 1}

, repulsive

Q. Two parallel wires $1 m$ apart carry currents of $1 A$ and $3 A$ respectively in opposite directions. The force per unit length acting between these two wires is

$6 \times 1 0^{- 7} N m^{- 1}$ repulsive

$6 \times 1 0^{- 7} N m^{- 1}$ attractive

$6 \times 1 0^{- 5} N m^{- 1}$ repulsive

$6 \times 1 0^{- 5} N m^{- 1}$ attractive

Q. Two parallel wires 1m apart carry currents of 1A and 3A respectively in opposite directions. The force per unit length acting between these two wires is

6×10−7Nm−1 repulsive

6×10−7Nm−1 attractive

6×10−5Nm−1 repulsive

6×10−5Nm−1 attractive

Q. Two parallel wires $1 m$ apart carry currents of $1 A$ and $3 A$ respectively in opposite directions. The force per unit length acting between these two wires is

$6 \times 1 0^{- 7} N m^{- 1}$ repulsive

$6 \times 1 0^{- 7} N m^{- 1}$ attractive

$6 \times 1 0^{- 5} N m^{- 1}$ repulsive

$6 \times 1 0^{- 5} N m^{- 1}$ attractive