Question

Equation F = ILB holds true only if:

• A. direction of electric current makes an angle of 30 degrees with the direction of magnetic field.
• B. direction of electric current makes an angle of 120 degrees with the direction of magnetic field.
• C. direction of electric current is perpendicular to the direction of magnetic field.
• D. direction of electric current is parallel to the direction of magnetic field.

Answer 1

The correct option is C direction of electric current is perpendicular to the direction of magnetic field.

The equation of the magnetic force on a current carrying wire in a magnetic field is given by
F = ILB sinθ (at any angle)
So, for the equation F = ILB to be true, sinθ should be equal to 1 and that is only possible when θ = 90, or in other words, when the direction of electric current is perpendicular to the direction of magnetic field.