Applications of Electromagnet in Everyday Life with Examples
Electromagnetism plays a crucial role in the working of various devices and systems around us. An electromagnet is a type of magnet where the magnetic field is produced by the flow of electric current. Unlike permanent magnets, the magnetic field of an electromagnet can be switched on or off, and its strength can be controlled by adjusting the current. Electromagnets are widely used in both household and industrial applications.
Understanding Electromagnets and Their Function
In basic terms, an electromagnet consists of a coil of wire, often wound around a core made from a material like soft iron. When an electric current passes through the coil, a magnetic field is generated around it. If the core is made of soft iron, the field produced is stronger and disappears rapidly when the current is stopped, making it ideal for applications where quick on-off control is required.
Principle of Electromagnetic Devices
The key principle behind an electromagnet is that a current-carrying coil creates a magnetic field. The field strength depends on the number of wire turns, the current through the coil, and the type of core material. This controllable magnetism allows engineers to design systems that need temporary or adjustable magnetic fields.
Common Uses and Practical Examples
Many everyday objects contain electromagnets. Electric motors, used in appliances and machines, rely on electromagnets to convert electrical energy into motion. Loudspeakers use electromagnets to create vibrations and produce sound.
Electric bells, such as those in schools, also contain electromagnets. When current flows, the electromagnet pulls a metal arm to strike a gong, producing a sound. Once the striker hits the gong, the circuit is broken, turning off the electromagnet. The arm springs back, reconnects the circuit, and the process repeats rapidly, keeping the bell ringing.
Large cranes in scrapyards often use electromagnets to lift heavy scrap cars or metallic debris. By switching the current on or off, the crane can easily pick up or drop ferrous materials. This controllable action is not possible with regular permanent magnets.
Electrically operated switches called relays also employ electromagnets. Relays enable circuit control at a distance and are fundamental in many control systems.
| Application | Working Principle | Purpose |
|---|---|---|
| Electric Bell | Electromagnet attracts striker when circuit closed | Produces ringing sound repeatedly |
| Electric Motor | Magnetic field from electromagnet causes rotation | Drives machinery, appliances |
| Loudspeaker | Electromagnet vibrates diaphragm via magnetic field | Converts electric signals into sound |
| Cranes (Scrapyard) | Magnetic field lifts/sets down metal objects | Moves heavy ferrous material easily |
| Relay Switch | Current energizes electromagnet to actuate switch | Enables remote/automatic circuit control |
How an Electric Bell Works – Stepwise Explanation
- The switch is open, the metal arm is away from the gong.
- The switch is closed, and current flows through the coil, creating a magnetic field.
- The electromagnet attracts the metal arm, making it hit the gong for a sound.
- The impact breaks the circuit, turning off the electromagnet. The metal arm springs back.
- Once the contacts touch again, the circuit completes, and the process repeats rapidly.
Key Formula: Magnetic Field of a Solenoid
The magnetic field (B) inside a long straight solenoid can be calculated using:
| Formula | Quantity | Unit |
|---|---|---|
| B = μ₀ × n × I | B = Magnetic field inside solenoid μ₀ = Permeability of free space n = Number of turns per meter I = Current through solenoid |
Tesla (T) |
Here, increasing the current (I) or number of coil turns (n) increases the field's strength, making the electromagnet more powerful.
Step-by-Step Problem-Solving Approach
- Identify the key quantities given (e.g., current, number of turns, solenoid length).
- Calculate number of turns per unit length: n = Total turns / Length.
- Use the formula B = μ₀ × n × I to find the magnetic field.
- Substitute values carefully and maintain units for accuracy.
Comparing Electromagnets and Permanent Magnets
| Property | Electromagnet | Permanent Magnet |
|---|---|---|
| Magnetism Control | Can be turned on/off | Always magnetic |
| Strength | Adjustable by varying current | Fixed strength |
| Typical Core Material | Soft iron (loses magnetism quickly) | Steel or special alloys |
| Applications | Motors, bells, cranes, relays | Compasses, static magnets |
Practice Problem Example
An electric bell contains an electromagnet. When the bell button is pressed, explain briefly what happens inside the device.
Answer: When the button is pressed, the circuit is completed and current flows through the electromagnet. The magnetic field attracts the striker, causing it to hit the gong. This breaks the circuit, turns off the electromagnet, and the striker returns to its original position. The cycle repeats rapidly, so the bell rings continuously while pressed.
Next Steps for Deepening Your Knowledge
- Review more examples and explanations on Uses of Electromagnet.
- Attempt practice questions on electromagnet applications, calculations, and circuit analysis.
- Explore related topics such as electric motors, electromagnetic induction, and relay switches on Vedantu’s Physics resource section.
Mastering how electromagnets function and where they are applied enriches your understanding of both fundamental Physics and its real-world technological impact.
FAQs on Uses of Electromagnets: Everyday Applications, Devices, and Importance
1. Why are electromagnets preferred in electric bells?
Electromagnets are preferred in electric bells because they provide controllable and temporary magnetism. The magnetism is only present when electric current flows, which allows the bell to ring repeatedly and stop instantly when the current is switched off. This enables efficient and reliable operation in electric bells.
2. Can electromagnets be as strong as permanent magnets?
Yes, electromagnets can be made as strong as or even stronger than most permanent magnets. Their strength increases when you:
- Increase the electric current flowing through the coil
- Increase the number of turns in the coil
- Use a soft iron core that enhances magnetic field strength
The adjustability of electromagnets makes them suitable for many high-power applications.
3. What is a key material for making electromagnets?
Soft iron is the preferred material for making the core of electromagnets because:
- It has high magnetic permeability (allows magnetic field lines to pass easily)
- It can be magnetized and demagnetized quickly
- This property makes electrical devices efficient and responsive
4. What are the top 5 uses of electromagnets?
The top 5 uses of electromagnets are:
- Electric bells (automatic ringing)
- Electric motors (converting electrical to mechanical energy)
- Loudspeakers and headphones (producing sound)
- Magnetic Resonance Imaging (MRI) machines in hospitals
- Cranes in scrapyards (lifting heavy magnetic materials)
5. How does an electromagnet differ from a permanent magnet?
An electromagnet’s magnetism is temporary and controllable, while a permanent magnet’s magnetism is constant. Key differences include:
- Electromagnets require electric current to produce magnetism; permanent magnets do not.
- The strength and polarity of an electromagnet can be varied by changing current direction or amount.
- Electromagnets can be switched on or off; permanent magnets always remain magnetic.
6. What are the advantages of using electromagnets over permanent magnets?
Electromagnets have several advantages:
- Their strength can be adjusted by changing the current
- Polarity can be reversed by reversing current direction
- They can be turned on and off, making them ideal for devices requiring controlled magnetism
7. Name three devices used in everyday life that work on the principle of an electromagnet.
Three common everyday devices that use electromagnets are:
- Electric bell
- Loudspeaker
- Electric relay or switch
8. How do cranes in scrapyards use electromagnets?
Cranes in scrapyards use large electromagnets to lift and move heavy iron or steel objects. When electric current flows, the electromagnet attracts scrap metal. To release the metal, the current is switched off and the magnetism disappears instantly.
9. What formula is used to calculate the magnetic field inside a solenoid (electromagnet)?
The magnetic field inside a long solenoid is given by: B = μ₀ × n × I, where:
- B = Magnetic field (Tesla)
- μ₀ = Permeability of free space (4π × 10⁻⁷ T·m/A)
- n = Number of turns per meter
- I = Current (Amperes)
10. What are some common misconceptions about electromagnets in exam questions?
Common misconceptions include:
- Confusing electromagnets with electromagnetic waves or electromagnetic induction
- Assuming electromagnets are always stronger than permanent magnets
- Forgetting that electromagnets require electric current to work
Clarity on definitions and applications helps avoid these errors in MCQs and theory questions.
11. Can the polarity of an electromagnet be changed?
Yes, the polarity of an electromagnet can be changed by reversing the direction of electric current in its coil. This property is useful in devices like motors and relays where directional control is needed.
12. How is an electromagnet constructed for school laboratory experiments?
To construct a simple electromagnet for experiments:
- Wrap insulated copper wire around a soft iron nail or rod
- Connect the coil ends to a battery or power source
- When current flows, the core becomes magnetic and can attract small iron objects
The magnetic effect disappears when the current is switched off.
