4.1.6
Electromagnets
Permanent Magnets and Electromagnets
Permanent Magnets and Electromagnets
You can create a magnet using a permanent magnet or by passing an electric current through a coil of wire (electromagnet).


Electromagnets
Electromagnets
- An electromagnet is made from a cylindrical coil of wire that has an electric current passing through it.
- An electromagnet is only magnetic when there is an electrical current flowing through it.
- When the electric current is switched off, the wire immediately loses its magnetism (is demagnetised).


Permanent magnets
Permanent magnets
- Permanent magnets are usually made from steel.
- These materials have strong magnetic fields and it is hard to remove their magnetism.
Increasing the Strength of an Electromagnet
Increasing the Strength of an Electromagnet
There are 3 ways to increase the strength of an electromagnet:


Iron core
Iron core
- To increase the strength of an electromagnet you can place a soft iron core inside the solenoid (cylindrical coil of wire).


More coils
More coils
- To increase the strength of an electromagnet you can increase the number of coils of wire.


Higher electric current
Higher electric current
- To increase the strength of an electromagnet you can increase the electric current flowing through the coils.
1Motion, Forces & Energy
1.1Physical Quantities & Measurement Techniques
1.2Motion
1.2.1Average Speed
1.2.2Calculating Average Speed
1.2.3Velocity
1.2.4Acceleration
1.2.5Distance-Time Graphs
1.2.6Speed-Time Graphs
1.2.7More Speed-Time Graphs
1.2.8Calculating Uniform Acceleration
1.2.9Gravity
1.2.10Free Fall - Distance-Time & Speed-Time Graphs
1.2.11Air Resistance
1.2.12Air Resistance - Graphs
1.2.13Optional: Calculating Acceleration
1.3Mass & Weight
1.5Forces: Effects of Forces
1.6Forces: Turning Effects of Forces
1.7Forces: Centre of Gravity
1.8Momentum
1.9Energy, Work, & Power: Energy
1.10Energy, Work & Power: Work
1.11Energy, Work & Power: Energy Resources
1.12Energy, Work & Power: Power
2Thermal Physics
2.1Kinetic Particle Model of Matter
2.2Thermal Properties & Temperature
3Waves
3.1General Properties of Waves
3.2Light: Reflection & Refraction
3.3Light: Thin Lenses
3.4Light: Dispersion of Light
3.5Electromagnetic Spectrum
4Electricity & Magnetism
4.1Simple Phenomena of Magnetism
4.2Electrical Quantities: Electric Charge
4.3Electrical Quantities: Electric Current
4.4Electromotive Force & Potential Difference
4.5Electrical Quantities: Resistance
4.6Electrical Energy & Electrical Power
4.7Electric Circuits: Circuit Diagrams & Components
4.8Electric Circuits: Series & Parallel Circuits
4.9Electric Circuits: Action & Use
4.10Electrical Safety
4.11Electromagnetic Effects: Electromagnetic Induction
4.12Electromagnetic Effects: The A.C. Generator
4.13Magnetic Effect of a Current
4.14Force on a Current-Carrying Conductor
4.15Electromagnetic Effects: The D.C. Motor
4.16Electromagnetic Effects: The Transformer
5Nuclear Physics
5.1The Nuclear Model of the Atom
5.2Radioactivity: Detection of Radioactivity
5.3Radioactivity: The Three Types of Nuclear Emission
6Space Physics
6.1The Earth & the Solar System
Jump to other topics
1Motion, Forces & Energy
1.1Physical Quantities & Measurement Techniques
1.2Motion
1.2.1Average Speed
1.2.2Calculating Average Speed
1.2.3Velocity
1.2.4Acceleration
1.2.5Distance-Time Graphs
1.2.6Speed-Time Graphs
1.2.7More Speed-Time Graphs
1.2.8Calculating Uniform Acceleration
1.2.9Gravity
1.2.10Free Fall - Distance-Time & Speed-Time Graphs
1.2.11Air Resistance
1.2.12Air Resistance - Graphs
1.2.13Optional: Calculating Acceleration
1.3Mass & Weight
1.5Forces: Effects of Forces
1.6Forces: Turning Effects of Forces
1.7Forces: Centre of Gravity
1.8Momentum
1.9Energy, Work, & Power: Energy
1.10Energy, Work & Power: Work
1.11Energy, Work & Power: Energy Resources
1.12Energy, Work & Power: Power
2Thermal Physics
2.1Kinetic Particle Model of Matter
2.2Thermal Properties & Temperature
3Waves
3.1General Properties of Waves
3.2Light: Reflection & Refraction
3.3Light: Thin Lenses
3.4Light: Dispersion of Light
3.5Electromagnetic Spectrum
4Electricity & Magnetism
4.1Simple Phenomena of Magnetism
4.2Electrical Quantities: Electric Charge
4.3Electrical Quantities: Electric Current
4.4Electromotive Force & Potential Difference
4.5Electrical Quantities: Resistance
4.6Electrical Energy & Electrical Power
4.7Electric Circuits: Circuit Diagrams & Components
4.8Electric Circuits: Series & Parallel Circuits
4.9Electric Circuits: Action & Use
4.10Electrical Safety
4.11Electromagnetic Effects: Electromagnetic Induction
4.12Electromagnetic Effects: The A.C. Generator
4.13Magnetic Effect of a Current
4.14Force on a Current-Carrying Conductor
4.15Electromagnetic Effects: The D.C. Motor
4.16Electromagnetic Effects: The Transformer
5Nuclear Physics
5.1The Nuclear Model of the Atom
5.2Radioactivity: Detection of Radioactivity
5.3Radioactivity: The Three Types of Nuclear Emission
6Space Physics
6.1The Earth & the Solar System
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