Which option correctly identifies the first right-hand rule in this context?

• A. Second right hand rule
• B. First right hand rule
• C. Third right hand rule
• D. Fleming's left-hand rule

Answer: (B)

The idea being tested is how a magnetic force is directed on a moving charge by the magnetic field, which comes from the cross product v × B. For a positive charge, use the right hand: point the index finger along the particle’s velocity, orient the middle finger along the magnetic field, and your thumb will point in the direction of the force. If the charge is negative, reverse the direction of the force. This is the first right-hand rule in this context because it directly gives the force direction from velocity and field using the cross product. Fleming’s left-hand rule is a different rule used for motors, and the other variants describe different relationships, so they don’t apply to this specific cross product direction.