The needle of a magnetic compass when placed...

🔍 Key Concepts

• Magnetic field around a current-carrying coil (electromagnet) and how its lines of force are arranged • How a magnetic compass needle behaves in an external magnetic field (it aligns with the local field lines) • The idea of a coil having an axis and effective magnetic north and south poles when current flows

💭 Think About

• Sketch the magnetic field lines of a simple solenoid (coil) and mark where the north and south poles would be. How do the lines run relative to the axis of the coil? • Ask yourself: does a compass needle align with the physical wire of the coil, or with the direction of the magnetic field lines produced by the coil? • Consider whether the needle would try to point toward one end (pole) of the coil, or simply line up along the general direction of the magnetic field inside and near the axis of the coil.

✅ Before You Answer

• Be clear on what is meant by the axis of the coil (an imaginary line running through the center of the loops, end to end) • Recall that a compass needle aligns with the direction of the magnetic field, not necessarily with the material object that creates it • Visualize or review the field pattern of a solenoid: which way are the lines inside the coil, and how would a free magnet (the compass needle) orient itself?

The needle of a magnetic compass when placed within a coil carrying an electric current:

Will tend to become parallel with the axis of the coil

Will point to the north pole end of the coil

Will point to the south pole end of the coil

A & B

🔍 Key Concepts

💭 Think About

✅ Before You Answer