A wire is pointing in a direction from northeast to southwes

A wire is pointing in a direction from north-east to south-west. a current of 650 mA is carried by the wire towards the south-west. The earth\'s magnetic field points due north with a strength of 0.45 x E-4 T. What force does the earth\'s magnetic field exert on the wire?

Solution

magnetic force = I*LxB = BILsin(thetha)

where thetha is angle b/w B and dl

=> magnetic force per unit length on the wire = 650*10^-3*0.45*10^-4*sin(45)

= 650*10^-3*0.45*10^-4*0.709 = 0.00002073 N

= 20.73*10^-6 N