P7 - Electromagnetism Flashcards
What is a magnetic field?
A magnetic field is the region around a magnet where magnetic forces can be detected.
What do magnetic field lines show?
Magnetic field lines show the direction of the magnetic field and the strength of the field (closer lines = stronger field).
What is Earth’s magnetic field?
Earth’s magnetic field is a large-scale magnetic field generated by the movement of molten iron in the Earth’s core.
What are the two poles of a magnet?
A magnet has a North pole and a South pole. Like poles repel; opposite poles attract.
What is the magnetic force?
A force exerted by magnetic fields on other magnets, magnetic materials, or moving charges.
What are permanent magnets?
Magnets that produce their own magnetic field and retain magnetism without the need for an external energy source.
What are induced magnets?
Materials that become magnetized when placed in a magnetic field but lose their magnetism when the field is removed.
What is electromagnetic induction?
The process of generating a current in a conductor by changing the magnetic field around it.
What is a magnetic material?
Materials that can be magnetized, such as iron, steel, cobalt, and nickel.
What is a solenoid?
A solenoid is a coil of wire that produces a uniform magnetic field when an electric current passes through it.
What factors affect the strength of a solenoid’s magnetic field?
The number of coils, the current, and the presence of a core material (like iron).
What is an electromagnet?
A magnet created by passing an electric current through a coil of wire, often with an iron core to increase its strength.
What does Fleming’s Left-Hand Rule predict?
Fleming’s Left-Hand Rule predicts the direction of force on a current-carrying conductor in a magnetic field (Thumb = motion, First finger = field, Second finger = current).
What is the motor effect?
The force experienced by a current-carrying conductor in a magnetic field.
How does an electric motor work?
An electric motor converts electrical energy into mechanical energy using the motor effect, with a coil of wire in a magnetic field.
How do electric generators work?
Electric generators convert mechanical energy into electrical energy using electromagnetic induction.
What is the difference between alternating current (AC) and direct current (DC)?
AC reverses direction periodically, while DC flows in one direction only.
What is a transformer?
A device used to change the voltage of an AC supply by increasing or decreasing the voltage using two coils of wire.
What is a step-up transformer?
A step-up transformer increases the voltage and decreases the current.
What is a step-down transformer?
A step-down transformer decreases the voltage and increases the current.
What is the magnetic field around a current-carrying wire?
A magnetic field forms concentric circles around the wire, with the direction determined by the right-hand rule.
What is an induced current?
An induced current is a current that is generated by changing the magnetic field around a conductor.
What factors affect the strength of a magnetic field?
The strength of a magnetic field depends on the current, the number of coils in a solenoid, and the material of the core (in the case of an electromagnet).
What are some applications of electromagnets?
Electromagnets are used in devices like motors, cranes, and magnetic levitation systems.
What is the magnetic force on a current-carrying wire?
A current-carrying wire experiences a force when placed in a magnetic field. The force depends on the current, the length of the wire, and the magnetic field strength.
How can the magnetic field of a solenoid be made stronger?
The magnetic field of a solenoid can be made stronger by increasing the current, increasing the number of coils, or inserting an iron core.
What are the uses of transformers?
Transformers are used in power distribution, adapting voltage levels to reduce energy loss over long distances.
