Magnetic compass, Storing of magnets
📚 Topic Overview: Magnetic Compass & Storing of Magnets
This section explains the working of a magnetic compass and the correct methods of
storing magnets. These concepts appear frequently in competitive exams due to their
real-life importance in navigation, safety, and practical use in laboratories.
1. Magnetic Compass
Concept / Theory
A magnetic compass is a simple direction-finding instrument. It contains a
small magnetic needle mounted freely on a pivot.
The needle aligns with Earth’s magnetic field, pointing towards the geographic
North and South directions.
Compasses are widely used by travellers, sailors, trekkers, and surveyors.
Working Principle
The compass works because Earth behaves like a giant bar magnet.
The compass needle, being a tiny magnet, aligns itself with Earth’s magnetic field.
Comparison Table
| Component | Function |
|---|---|
| Magnetic Needle | Aligns N–S direction |
| Dial | Shows directions (N, S, E, W) |
| Pivot | Allows free rotation |
| Case | Protects the needle |
Analogy / Examples
- A compass needle behaves like a tiny bar magnet floating on a pivot.
| English | Telugu |
|---|---|
| Compass | దిక్సూచి |
| Needle | సూది |
| Direction | దిశ |
Fishermen use compasses while sailing far from shore. Even when mobile signals
and GPS fail, a magnetic compass still shows the correct direction because it
relies on Earth’s magnetic field.
If a compass needle gets deflected near electric wires or magnets, the correct
answer is: “External magnetic field is interfering with it.”
2. Storing of Magnets
Concept / Theory
Magnets should be stored carefully to prevent loss of magnetism. Improper
storage such as dropping, heating, or placing magnets with like poles together
weakens them over time.
For long-term storage, magnets are kept with
soft iron keepers which complete a closed magnetic path.
Correct Storage Method
| Magnet Type | Storage Method |
|---|---|
| Bar Magnets | Stored in pairs with opposite poles joined & keepers |
| Horseshoe Magnets | Stored with keeper connecting two poles |
| Ring Magnets | Stacked neatly to avoid demagnetization |
Why Keepers Are Used?
- Keepers reduce magnetic leakage.
- Maintain domain alignment inside the magnet.
- Prevent loss of strength.
| English | Telugu |
|---|---|
| Keeper | లోహపు పట్టీ |
| Storage | నిల్వ |
| Demagnetization | చుంబకత్వం కోల్పోవడం |
In school laboratories, bar magnets are stored in wooden boxes with soft iron
keepers to protect them from losing magnetic strength over the academic year.
A common MCQ asks: “Magnets should be stored with a ______.”
The correct answer is: Soft iron keeper.
3. Exam Tips & Tricks + Memory Sheet + Sample Questions
Memory / Formula Sheet
- Compass Needle → Always points N–S
- Earth = giant bar magnet
- Compass disturbance = external magnetic field
- Store magnets with keepers
- Avoid heat, hammering, dropping
- Horseshoe magnet → strongest at poles
Typical Exam Questions (Pattern Matching)
- Why does a compass needle get disturbed near a mobile tower or power line?
- What will happen if a bar magnet is stored without a keeper for months?
- Fishermen still use magnetic compasses. Why?
- Which instrument works even during power failure: compass or GPS?
- Which method prevents demagnetization of bar magnets?
Most MCQs on this topic are application-based. They test “What happens if…?”
rather than “What is…?”. Always imagine a real-life scenario.