Question

Iron filings are sprinkled on a cardboard perpendicular to which a current carrying copper wire runs. The other components of the circuit have their usual meanings

The deflection in the compass needle decreases as the compass is moved away from the copper wire. This tells that:

• A. The magnetic field strength increases as the distance from the wire increases
• B. The magnetic field strength decreases as the distance from the wire increases
• C. There is no change in the magnetic field strength
• D. The magnetic field alters its direction as distance from the wire increases

Answer 1

The correct option is B

The magnetic field strength decreases as the distance from the wire increases

Magnetic field intensity decreases as the distance from the current carrying conductor (or magnet) increases. As magnetic field intensity decreases, the deflection of the compass needle decreases.