Question

A magnetic compass shows a deflection when placed near a current carrying wire. If the current in the wire is increased, How does the deflection of the compass gets affected ?

• A. increased
• B. data insufficient
• C. decreased
• D. remain same

Answer 1

Answer: (A)

When a magnetic compass is brought close to a current carrying wire there is deflection in the compass due to the formation of magnetic field. The magnetic field lines around a long wire which carries an electric current form concentric circles around the wire. The direction of the magnetic field is perpendicular to the wire.
The deflection increases when the current is increased because the magnitude of the field is directly proportional to the strength of the electric current. That is, stronger the electric field, stronger the magnetic field.