Which statement best describes the right-hand rule for current and magnetic field?

Which statement best describes the right-hand rule for current and magnetic field?

• A. The thumb indicates the direction of the current and the fingers show the direction of the magnetic field.
• B. The thumb indicates the direction of the magnetic field and the fingers show the current.
• C. The palm indicates the direction of force.
• D. The fingertips indicate the charge.

Answer: (A)

The right-hand rule links the direction of conventional current to the magnetic field around a conductor. If you point the thumb of your right hand along the direction of the current, your curled fingers sweep in the direction of the magnetic field lines that form circles around the wire. This is exactly what the statement describes, so it’s the best way to visualize the relationship between current and the surrounding magnetic field. Think of the field around a long straight wire as concentric circles around the wire; using the right hand this way makes the field direction clear at any point. The other descriptions don’t match this standard visualization: the palm isn’t used to indicate a force in this rule, and fingertips don’t describe charge direction in this context. For completeness, remember that actual electron flow is opposite to the conventional current, but the rule is stated in terms of conventional current.

The right-hand rule links the direction of conventional current to the magnetic field around a conductor. If you point the thumb of your right hand along the direction of the current, your curled fingers sweep in the direction of the magnetic field lines that form circles around the wire. This is exactly what the statement describes, so it’s the best way to visualize the relationship between current and the surrounding magnetic field.

Think of the field around a long straight wire as concentric circles around the wire; using the right hand this way makes the field direction clear at any point. The other descriptions don’t match this standard visualization: the palm isn’t used to indicate a force in this rule, and fingertips don’t describe charge direction in this context. For completeness, remember that actual electron flow is opposite to the conventional current, but the rule is stated in terms of conventional current.