If a 242 mm long conductor experiences a force of 0.75 N when carrying a current of 640 mA perpendicular to a magnetic field, what is the approximate magnetic flux density?

A conductor carrying current is placed in a uniform magnetic field. If the conductor length is doubled and current is halved, what happens to the magnetic force on the conductor?

The magnetic field at a point P situated at a perpendicular distance 'R' from a long straight wire carrying a current of 12 A is 3 × 10-5 Wb/m2. The value of 'R' in mm is: (Take μ0 = 4π × 10-7 Wb/A·m)