Question

Two long and straight conductors, placed parallel to each other are separated by 20 cm. carrying current of 3A and 5A respectively in opposite direction. The force per unit length exerted by each conductor on the other is (µ₀ = 4π x 10^-7 Wb/Am)

Options

• `1.5 xx 10^-5 "N"/"m"`, attractive

• `1.5 xx 10^-5 "N"/"m"`, repulsive

• `3 xx 10^-5 "N"/"m"`, repulsive

• `3 xx 10^-5 "N"/"m"`, attractive

Answer 1

`1.5 xx 10^-5 "N"/"m"`, repulsive

Explanation:

a = 20 cm = 0.2 m

i₁ = 3 A  h = 5 A

F = `mu_0/(4pi) xx (2"i"_1"i"_2)/"a"`

`= (10^-7 xx 2 xx 3 xx 5)/0.2`

`= 10 xx 3 xx 5 xx 10^-7`

= 15 × 10^-6

= 1.5 × 10^-5 N/m