The magnetic force on a moving charge in a magnetic field acts
A. Only at right angles to the direction of motion of the particle
B. Only at right angles to magnetic field
C. At right angles to the field and the direction of motion of the particle
D. Parallel to the field as well as the direction of the motion of the particle

Hint: Magnetic field exerts the force on charge moving through the magnetic field and the direction of the magnetic force on a moving charge follows the right hand rule (RHR), which is implemented using index figure, middle finger and thumb of the right hand, as shown in the figure below.


Complete step by step answer:In magnetic electricity, we know that magnetic field exerts force on moving charge. The direction and magnitude of the charge is determined by the right hand rule (RHR).
The right hand rule states: if the thumb, the forefinger, and the middle finger of the right hand are bent at right angles to one another with the first finger pointed in the direction of motion of a magnetic field and the middle finger in the direction of the motion of the charged particle, then the thumb will point in the direction of the force.
So, we can safely say that the magnetic force on a moving charge in a magnetic field acts at right angles to the field and the direction of motion of the particle.
The magnitude of the force is determined by multiplying the magnitude of force of the field, magnitude of force of the particle and sin of the angle made between the field and the direction of the moving particle.

Note:This law can be used to determine the force exerted on an electric conductor, when the conductor is carrying the electric charge and it is under the influence of a magnetic field around it. The real life applications of this force ranges from TV, video tape, audio tape to magnetic levitation trains.