Solenoid

1. Identify the coil with many turns. 2. State that current in the coil produces a magnetic field. 3. Mention the north and south poles at opposite ends. 4. Add that the field inside is strong and nearly uniform.

Draw a cylindrical coil with arrows showing current and field lines inside the coil as nearly parallel, crowded lines.

A common wrong answer is that the solenoid always acts as a magnet without current. That is wrong because current is needed to produce the field.

A solenoid is a long cylindrical coil of many turns of insulated wire.

A solenoid is a long cylindrical coil of many turns of insulated wire. A current-carrying solenoid behaves like a bar magnet, with a strong and nearly uniform field inside the coil. A tightly wound coil used in an electric bell or relay is a practical solenoid-based arrangement.

When current flows through a solenoid, it produces a magnetic field similar to that of a bar magnet. One end behaves like a north pole and the other like a south pole. The field inside a solenoid is strong and nearly uniform in the middle region. This is why solenoids are used to make electromagnets and many electric devices. A current-carrying solenoid behaves like a bar magnet, with a strong and nearly uniform field inside the coil. If a battery is connected to a coil of wire wound around a nail, the nail becomes magnetic while current flows. The coil acts as a solenoid and the nail becomes an electromagnet core. Define a solenoid, describe its field pattern, or explain why it behaves like a bar magnet when current flows. A common wrong answer is that the solenoid always acts as a magnet without current. That is wrong because current is needed to produce the field.