Magnetism Basics
What are the two types of magnetic poles?
North and South
What is the relationship between electricity and magnetism?
Moving electric charges produce a magnetic field.
What is electromagnetic induction?
The process of generating an electric current by changing a magnetic field.
What is the function of a galvanometer?
It measures small electric currents using a magnetic field and a moving coil.
Describe how a compass needle moves in a magnetic field.
It aligns with the magnetic field, pointing toward the Earth's magnetic north pole.
What happens when two like magnetic poles are placed near each other?
They repel each other.
Who discovered that an electric current produces a magnetic field?
Hans Christian Oersted.
What type of energy transformation occurs in a generator?
Mechanical energy is converted into electrical energy.
What is the role of a magnetic domain in magnetism?
Magnetic domains are small regions where atoms are aligned, creating a net magnetic field.
Why does a magnet exert a force on another magnet even if they are not touching?
Magnets create an invisible magnetic field that exerts forces on other magnets at a distance.
How does the distance between magnets affect their magnetic force?
The force increases when they are closer together and decreases when they are farther apart.
What happens to the direction of a magnetic field when the electric current is reversed?
The magnetic field reverses direction.
What is the difference between AC (alternating current) and DC (direct current)?
AC reverses direction periodically, while DC flows in only one direction.
How does heating a bar magnet affect its magnetic field?
Heating disrupts the alignment of magnetic domains, weakening or destroying the magnetism.
What happens when a magnet is placed near a current-carrying wire?
The magnet experiences a force due to the magnetic field created by the moving charges in the wire.
What is the Earth's magnetic field, and what generates it?
Earth's magnetic field is generated by the movement of molten iron and nickel in the outer core.
Name two ways to increase the strength of an electromagnet.
Increase the current or add more coils of wire.
What is the purpose of a transformer in electrical transmission?
It changes the voltage of an alternating current to reduce energy loss during transmission.
What is a solenoid?
A coil of wire that produces a magnetic field when an electric current passes through it.
Explain why a magnet sitting next to a wire does not induce a current.
A current is only induced if the magnet is moving or if the magnetic field is changing.
Explain why some materials are magnetic while others are not.
Only materials with unpaired electrons and aligned magnetic domains (like iron, cobalt, and nickel) can be magnetized.
How does an electric motor work?
It uses electromagnets to convert electrical energy into mechanical energy by rotating a coil in a magnetic field.
How do step-up and step-down transformers differ?
Step-up transformers increase voltage, while step-down transformers decrease voltage.
Describe how a speaker uses electromagnetism to produce sound.
A changing electric current flows through a coil, creating a magnetic field that moves a diaphragm, producing sound waves.
How does a generator use electromagnetic induction to produce electricity?
A rotating magnet inside a coil of wire changes the magnetic field, inducing an electric current.