20.1 Physics Flashcards
Induction aside, how do charges move in the presence of an electrical power supply?
The electrical power supply creates a potential difference within a current, and the electric field associated with that potential difference causes the charges to move through the circuit.
How can you induce a current without a battery/electrical power supply?
You can do so by placing a closed electric circuit perpendicular to or at an angle to a magnetic field. One of them needs to be moving though, or both in opposite directions.
This is called electromagnetic induction
What induced an emf?
The seperation of charges by the magnetic force
For free positive charges in a wire pulled through a magnetic field, where is the force direction towards?
The force is directed downward along the wire
For free negative charges in a wire pulled through a magnetic field, where is the force direction towards?
The force is directed upward along the wire
What is the equivalent of positive charges moving downward, and negative charges moving upward as a result of a magnetic field?
It’s the equivalent of a battery that has a potential difference/emf between its terminals.
The question’s contraption has an emf btw as does the battery
The polarity of the induced emf depends on what?
It depends on the direction in which the wire is moved through the magnetic field.
If the wire is moved to the right, what does the right hand rule predict?
It predicts that the negative charges will be pushed upward.
This is the predicted polarity
If the wire is moved to the left, what does the right hand rule predict?
It predicts that the negative charges will be pushed downward.
ريان
How does angle affect induction?
a. The current is the largest when the plane of the loop is perpendicular to the magnetic field
b. The current is smaller when the loop is titled into the field
c. The current is zero if the plane is parallel to the field
How can a current be induced without moving the magnetic field or the loop/wire?
By changing the number of magnetic field lines or the size of the loop
Specify how a current be induced without moving the magnetic field or the loop/wire.
- Moving a circuit into and out a magnetic field (circuit or magnet moving)
- Rotating a circuit in the magnetic field (angles between area of circuit and magnetic field change)
- Changing the intensity and/or the direction of tge field
When a magnet is moving towards a coil, which direction is the coils current moving?
It’s moving in the opposite direction of the magnet
And the magnetic field the current induces is towards the magnet
When a magnet is moving awa from a coil, which direction is the coils current moving?
It’s moving in the towards the magnet
And the magnetic field the current induces is away from the magnet
What’s the rule to finding the direction of an induced current?
Lenz’s law
