Two long parallel wires are at a distance of 1 metre. Both of them carry one ampere of current. The force of attraction per unit length between the two wires is

Question

Two long parallel wires are at a distance of 1 metre. Both of them carry one ampere of current. The force of attraction per unit length between the two wires is (A) 5 × 10 -8 N/m (B) 2 × 10 -8 N/m (C) 2 × 10 -7 N/m (D)  10 -7 N/m

Tardigrade Admin · Accepted Answer

F= (μ0 /4 π) (2 I1 I2/r) = ( 10 -7 × 2(1) × (1)/1) = 2 × 10-7 N/m

Q. Two long parallel wires are at a distance of $1$ metre. Both of them carry one ampere of current. The force of attraction per unit length between the two wires is

$5 \times 10^{- 8} N / m$

$2 \times 10^{- 8} N / m$

$2 \times 10^{- 7} N / m$

$10^{- 7} N / m$

$F = \frac{μ _{0}}{4 π} \frac{2 I _{1} I _{2}}{r} = \frac{10 ^{- 7} \times 2 ( 1 ) \times ( 1 )}{1}$
$= 2 \times 10^{- 7} N / m$

Q. Two long parallel wires are at a distance of 1 metre. Both of them carry one ampere of current. The force of attraction per unit length between the two wires is

5×10−8N/m

2×10−8N/m

2×10−7N/m

10−7N/m