Magnetic force on moving electrons via right-hand rule

Steps:

• Determine electron velocity direction (typically rightward on page).
• Identify magnetic field direction (typically into the page).
• Apply right-hand rule for positive charge: fingers in velocity direction, curl toward B field, thumb points up; reverse for negative electron charge.
• Force direction is downward, deflecting electrons down the page.

Why D is correct:

• Lorentz force law F = q(v × B) yields downward direction for negative q, rightward v, and B into page.

Why the others are wrong:

• A: Would require B out of page.
• B: Matches positive charge deflection, not electrons.
• C: Applies to positive charges in this setup.

Final answer: D