Question

​A horizontal wire 12 m long carrying a current of 20 A due north passes through a 0.75 T horizontal magnetic field that points 60o north of west. What size magnetic force acts on this wire?

also what is the directiom of the force acting on the magnetic wire?

Answer 1

Magnetic force on current carrying wire is given by,

= L*(x)

given, L = length of wire = 12 m

= current in wire = 20 A due north = 20 j

= magnetic field = 0.75 T 60 deg north of west

= -0.75*cos(60 deg) i + 0.75*sin(60 deg) j

= -0.375 i + 0.65 j

So,

= 12*(20 j)x(-0.375 i + 0.65 j)

= -12*20*0.375 (jxi) + 12*20*0.65 (jxj)

Since, jxj = 0 ; jxi = -k

So, = 12*20*0.375 k

= (90 N) k

1.

size of magnetic force acts on this wire(||) = 90 N

2.

the direction of the force acting on the magnetic wire = k = upward direction Or positive z-axis