Two parallel wires in free space are 10 cm apart and each carries a current of 10 A in the same direction. The force exerted by one wire on the other [per unit length] is

Question

Two parallel wires in free space are 10 cm apart and each carries a current of 10 A in the same direction. The force exerted by one wire on the other [per unit length] is (A) 2 × 10-4 Nm -1 [attractive] (B) 2 × 10-7 Nm -1 [attractive] (C) 2 × 10-4 Nm -1 [repulsive] (D) 2 × 10-7 Nm -1 [repulsive]

Tardigrade Admin · Accepted Answer

( F /l) =((μ0/4 π)) (2 I 1 I 2/ d ) =(10-7 × 2 × 10 × 10/10 × 10-2) ( F /l)=2 × 10-4 N m -1 [attractive since the currents are in the same direction]

Q. Two parallel wires in free space are $10 c m$ apart and each carries a current of $10 A$ in the same direction. The force exerted by one wire on the other [per unit length] is

$2 \times 1 0^{- 4} N m^{- 1}$ [attractive]

$2 \times 1 0^{- 7} N m^{- 1}$ [attractive]

$2 \times 1 0^{- 4} N m^{- 1}$ [repulsive]

$2 \times 1 0^{- 7} N m^{- 1}$ [repulsive]

$\frac{F}{l} = (\frac{μ _{0}}{4 π}) \frac{2 I _{1} I _{2}}{d}$
$= \frac{1 0 ^{- 7} \times 2 \times 10 \times 10}{10 \times 1 0 ^{- 2}}$
$\frac{F}{l} = 2 \times 1 0^{- 4} N m^{- 1}$
[attractive since the currents are in the same direction]

Q. Two parallel wires in free space are 10cm apart and each carries a current of 10A in the same direction. The force exerted by one wire on the other [per unit length] is

2×10−4Nm−1 [attractive]

2×10−7Nm−1 [attractive]

2×10−4Nm−1 [repulsive]

2×10−7Nm−1 [repulsive]