P4.5.3 - Magnetic Effect of Current Flashcards
When are magnetic fields formed? [1]
- wherever a current flows
What are examples of where magnetic fields are used in? [2]
- straight wires
- solenoids
Describe the magnetic field due to a straight wire. [2]
- magnetic field lines around a straight wire are made up on concentric circles
- it indicates that a current-carrying wire has no poles
What is the right-hand grip rule used for? [1]
used to work out the direction of the magnetic field
What does the direction of the field lines around the wire depend on? [1]
depends on the direction of the current
What does reversing the current do? [1]
reverses the direction of the field
What is a solenoid? [1]
it is a long insulated current carrying coil
How does an electromagnet and a solenoid work together? [2]
- increases the strength of the magnetic field
- by adding more turns of wire into a smaller region of space
What does the magnetic field set up by a solenoid look like? [3]
- looks like a bar magnet
- one end = north pole
- another end = south pole
What does the right-hand grip rule determine? [1]
- determines the poles of the solenoid (like which one is north and which one is south)
How do you use the right-hand grip rule? [2]
- grip hand so that fingers curl in the direction of the current
- the direction pointed by the thumb is the direction of the north pole
How can the strength of the magnetic field produced around a wire be increased? [1]
increase the amount of current flowing through the wire
How can the direction of the magnetic field produced around a wire be changed? [1]
by changing the direction of the current
How is the strength of the magnetic field in relation to distance? [2]
- strength decreases with distance
- strength is strongest when near the wire
How is the weakness of the magnetic field away from a wire shown? [1]
the magnetic field lines become more further apart
