Important notes and tips i want my sec 4 physics students to remember on this topic. Yes, you read it correctly. REMEMBER the following points! 🙂
- A freely suspending magnet comes to rest with its N pole pointing North.
- Solenoid is a long coil of insulated wire.
- One way of demagnetism is to insert a magnet into a solenoid connected to a a.c. supply. Slowly withdraw the magnet while the current is switched on.
- A magnetic field is the region around the magnet where other magnetic materials experience a force.
A compass will always point in the same direction of the magnetic field lines. Hence, the pointer of the compass arrow will ALWAYS point away from north pole towards South pole.
- Temporary magnets examples: circuit breaker, electric bells
- Permanent magnet examples examples: compasses, magnetic door catches
- When a magnet is brought near a magnetic substance, the magnetic substance becomes a induced magnet with the end nearer to the magnet having a opposite pole to the magnet. Then attraction occurs.
- Magnetic material will concentrate the field lines but non magnetic material will not.
- Summary for Right Hand Grip Rule
Straight wire: Thumb points to current, finger to magnetic field
Solenoid: Thumb points to magnetic field/ north pole. Fingers to current.
- Fleming’s left hand rule is used for determining the direction of the force on a current-carrying conductor.
Current starts with C. (Third alphabet in ABC) –> Third finger.
Thumb is the first finger hence imagine its most powerful. So it points to the Force. 🙂
Thats all, kiddos.
Will test u all next lesson.