Question

Each of two long straight parallel wires separated by a distance of 16 cm carries a current of 20 A in the same direction. What is the magnitude of the resulting magnetic field at a point that is 10 cm from each wire?

a)		80  micro Teslas
b)		48 micro Teslas
c)		57  micro Teslas
d)		40  micro Teslas
e)		64  micro Teslas

Answer 1

The following figure shows the direction of the resultant magnitude as follows 28co Refer figure 1, sin θ cm 10 cm 0.8 cm Thus, e -sin-1(0.8 53.13 The magnetic field due to each wire is as follows 4x10 T m/A)(20A) T(0.10 m) =40x10-6 T Due to symmetry, the vertical compoOnent of the magnetic field cancel out Thus, the net magnetic field is, - 2(40x10- T)cos 53.13 -48x10-5 T Hence, the correct option is b