Answer to Question #301533 in Electricity and Magnetism for aimi

Question

two parallels wires, wire P and Q which carries a current of 30A and 50A, respectively in the same direction.The wires are placed 1.25 mm apart in a vacuum.

a) Calculate the magnetic force per unit length on wire P.

b) Determine the position x from wire P in between the wires where the magnetic field is zero.

Answer 1

a)

$F= \frac{ μ _ 0 ​ I _ 1 ​ I _ 2}{2\pi d} ​ ​ =240 mN,$

b)

$x=\frac{dI_1}{I_2}=0.75~mm.$