Right-hand rule determines magnetic field direction around a current-carrying wire

Steps:

• The wire is vertical with current flowing upward; observer views from above, so current points toward observer.
• Apply right-hand rule: thumb points in current direction (out of page toward observer).
• Fingers curl counterclockwise, showing magnetic field lines form concentric circles in that direction.
• Pattern appears as counterclockwise loops when viewed from this position.

Why D is correct:

• D shows counterclockwise circular field lines, matching Ampere's right-hand rule for current directed toward the observer.

Why the others are wrong:

• A shows clockwise circles, opposite to right-hand rule direction.
• B shows linear field lines, incorrect as fields are circular around a straight wire.
• C shows radial lines from wire, wrong as fields are tangential, not diverging.

Final answer: D