Magnets Flashcards
Describe the pattern of a magnetic field due to a bar magnet
A bar magnetâs magnetic field forms loops from its north to south pole.
The field lines come out from the north pole, curve around the magnet, and return to the south pole.
The field lines are evenly spaced and run parallel to each other.
Describe the pattern of a magnetic field due to a combination of magnets
When magnets are combined, their magnetic fields interact and create a new magnetic field pattern.
The pattern depends on how the magnets are arranged.
The field lines flow from one magnetâs north pole to another magnetâs south pole, forming a continuous loop.
Describe the pattern of a magnetic field due to currents in a straight wire
When a current flows through a straight wire, the magnetic field forms circles around the wire. Use the right-hand rule:
If you point your thumb in the direction of the current, the curled fingers show the direction of the magnetic field lines around the wire.
Describe the pattern of a magnetic field due to currents in a solenoid
When current flows through it, the magnetic field inside the solenoid is strong and even, running parallel to the coilâs axis.
Outside the solenoid, the magnetic field lines form loops like a bar magnet, exiting from one end and entering the other.
(A solenoid is a coil of wire with many turns. )
Describe the effect on the field of changing the magnitude and direction of the current
Increasing the current makes the magnetic field stronger, while decreasing the current weakens it. Changing the direction of the current reverses the orientation of the magnetic field lines.
State the effect of the number of coilsâ impact on the magnetic field created by an electromagnet.
Adding more coils to an electromagnet strengthens the magnetic field. With more coils, there are more turns of wire, which leads to a greater magnetic field when current flows through them.
State the effect of the currents impact on the magnetic field created by an electromagnet.
The strength of the magnetic field is directly proportional to the current flowing through the coils of the electromagnet. Increasing the current increases the magnetic field strength while decreasing the current weakens it.
State the effect of the material for the coreâs impact on the magnetic field created by an electromagnet.
The material used for the core of an electromagnet affects its magnetic field. Using a ferromagnetic material like iron strengthens the magnetic field by focusing and concentrating the magnetic flux. Non-magnetic or weakly magnetic materials are less effective in enhancing the magnetic field.
State that the field strength at a point is represented by the density of field lines
The density of field lines represents the field strength at a point. Closer field lines indicate a stronger magnetic field, while more spread-out field lines indicate a weaker magnetic field.
Why is voltage induced when a conductor is moved relative to a magnetic field?
Moving a wire in a magnetic field or changing the magnetic field near a wire generates an electric voltage.
This occurs because the changing magnetic field creates an electric current in the wire, which leads to a voltage across the wire.
Describe how rate of change in magnetic field impact the voltage induced
According to Faradayâs law, the induced voltage is higher when the magnetic field changes quickly and lower when it changes slowly.
Describe how number of coils impact the voltage induced
Increasing the number of coils increases the amount of wire exposed to the changing magnetic field. This, in turn, leads to a higher voltage induced. Conversely, reducing the number of coils decreases the induced voltage.
Outline how a generator works
A generator works by rotating a coil of wire within a magnetic field. This rotation induces a voltage in the coil, which produces an alternating current (AC) in the wire. The AC is then collected and can be used to power electrical devices.
What is Flemingâs Left Hand Rule?
Thumb = Force
Index = Magnetic Field
Middle = Current
