Which statement is true about a coil's magnetic field when current increases?

Which statement is true about a coil's magnetic field when current increases?

• A. Increasing the current through the coil strengthens its magnetic field
• B. Increasing the current weakens its magnetic field
• C. The magnetic field is unchanged
• D. Current does not affect magnetism

Answer: (A)

When current flows through a coil, moving charges produce a magnetic field. In a fixed coil, increasing the current makes more field lines and increases the field’s strength (the field inside a solenoid is proportional to the current, B ∝ I, with additional dependence on turns per length). So pushing more current through strengthens the magnetic field, not strengthens it weakly or leaves it unchanged. The direction of the field follows the right-hand rule, but the key idea is that current and magnetism grow together: more current means a stronger magnetic field.

When current flows through a coil, moving charges produce a magnetic field. In a fixed coil, increasing the current makes more field lines and increases the field’s strength (the field inside a solenoid is proportional to the current, B ∝ I, with additional dependence on turns per length). So pushing more current through strengthens the magnetic field, not strengthens it weakly or leaves it unchanged. The direction of the field follows the right-hand rule, but the key idea is that current and magnetism grow together: more current means a stronger magnetic field.