Magnetism Flashcards
(19 cards)
What force occurs between two NORTH poles?
Repulsion
Name three magnetic materials.
Iron, Nickel, Cobalt
In which direction do magnetic field lines point outside a magnet?
From NORTH to SOUTH
Where is a magnet’s magnetic field strongest?
At the poles
Why is iron considered an ‘induced’ magnet?
Only magnetic when in a field; loses magnetism quickly
What creates a magnetic field around a straight wire?
Electric current
How do you determine magnetic field direction around a wire?
Right-hand grip rule: thumb points in current direction
What type of magnetic field exists inside a solenoid?
Strong, straight, and uniform
How do you find a solenoid’s NORTH pole?
Right-hand grip rule: thumb points to N-pole
Why is iron preferred over steel for electromagnet cores?
Iron demagnetizes quickly; steel stays magnetic longer
Name three ways to increase electromagnet strength.
Increase current, add more coil turns, use iron core
What two conditions create the motor effect force?
Current-carrying wire in external magnetic field
What does each finger represent in Fleming’s Left-Hand Rule?
Thumb=Motion, First=Field (N→S), Second=Current
What is the equation for motor effect force?
F = B × I × L
What are the units for B (flux density), I (current), and L (length)?
Tesla (T), Amps (A), Meters (m)
What component reverses current in a DC motor every half-rotation?
Split-ring commutator
What is the function of carbon brushes in a motor?
Connect power supply to spinning commutator
How can you make an electric motor spin faster?
Increase current, use stronger magnets, add more coil turns
How is motor effect force measured experimentally?
Measure force change on top-pan balance with current
