Magnets
What is the term for the area around a magnet where magnetic force is exerted?
Magnetic Field
What device creates a magnetic field using electric current?
What is the main function of an electric motor?
To convert electrical energy to mechanical energy
What is the primary purpose of an electric generator?
The generator converts mechanical energy into electrical energy.
What is a galvanometer used for?
To measure electrical current
What are the two types of magnetic poles called?
North and South
How can you increase the strength of an electromagnet?
Options:
- Use a stronger battery
- Increase the number of coils in the wire
- Add a ferromagnetic core
What are the five principal components of an electric motor?
1.) Stator
2.) Rotor
3.) Commutator
4.) Brushes
5.) Axle
How does an electric generator convert mechanical energy into electrical energy?
What does the needle of a galvanometer indicate?
How high or low the voltage output is
Name a common material that is attracted to magnets
Options:
Iron
Cobalt
Nickel
In which applications are electromagnets commonly used?
Options:
- Electronics like phones and laptops
- Motorized items like cars, fridges, and fans
- Generators found in power plants
Etc.
How does an electric motor convert electrical energy into mechanical energy?
Simply, the stator creates an electrical field that interacts with the rotor. The rotor spins and the energy is transported through the commutator and brushes to the axle to produce mechanical energy in the device.
What is the principle of electromagnetic induction?
If we have a changing magnetic field within a closed loop of wire, there is an electromotive force (EMF) or voltage in the wire. Meaning, changing the magnetic field will cause a change resulting in electrical charge.
How does a galvanometer measure current?
A coil is placed within a permanent magnetic field. The interaction between the magnetic field of the coil and the external magnetic field produces a torque on the coil. This torque causes the coil to rotate. The amount of rotation (deflection) of the coil is proportional to the strength of the current flowing through it. As the coil rotates, the attached pointer moves along the scale, providing a visual indication of the current magnitude.
What happens when you break a magnet in half?
You have two smaller magnets, both with a north and south pole.
The magnet DOES NOT become a north pole and a south pole
What is the relationship between current and magnetic field strength in an electromagnet?
They are DIRECTLY RELATED. Meaning, as one increases, the other will too and vice versa.
What role does the commutator play in an electric motor?
The commutator reverses the direction of the electrical current, therefore reversing the poles continuously. This allows the rotor to keep spinning to produce mechanical energy.
Name one type of energy source that can be used to power a generator
Options:
- Coal
- Nuclear power
- Wind
- Water
- Sunlight (photons)
What is the difference between a galvanometer and an ammeter?
An ammeter primarily measures magnitude while a galvanometer shows magnitude as well as how the current flows from positive to negative (direction).
What is the principle that explains why a compass needle points north?
Earth has a magnetic field from the iron in its core. The compass needle is attracted either to the north or south pole of Earth's poles.
Describe how reversing the current direction affects the electromagnet
The magnet's poles will reverse too. North becomes south and south becomes north.
Describe how the interaction between magnetic fields and current produces motion in a motor
The electrical current and magnetic fields created in the stator and coils of the electromagnets exert force on one another which causes movement and rotation.
How does the speed of rotation affect the output voltage of a generator?
The higher the speed of rotation, the greater electrical output of the generator.
This comes from the idea that the magnetic field and electrical output are directly related.
Explain the principle behind how a galvanometer works
A galvanometer typically consists of a coil of wire suspended in a magnetic field. The coil is able to rotate freely. There is also a pointer attached to the coil that moves along a scale.
When an electric current passes through the coil, it generates a magnetic field around the coil. The direction of the magnetic field depends on the direction of the current flow.
The coil is placed within a permanent magnetic field. The interaction between the magnetic field of the coil and the external magnetic field produces a torque on the coil. This torque causes the coil to rotate.
The amount of rotation of the coil is proportional to the strength of the current flowing through it. As the coil rotates, the attached pointer moves along the scale, providing a visual indication of the current magnitude.