educake - Magnetism and the motor effect Flashcards
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magnetic field defenition
the region around a magnet where a force acts on another magnet.
What units are used for magnetic flux density?
tesla (T)
When using Fleming’s left-hand rule, the second (middle) finger points in the direction of the…
current
Will there be a force on a current-carrying wire in a magnetic field if the current and fields are parallel?
no
The current and the magnetic field lines need to be at right angles to produce a force.
induced magnet defenition
a magnet that becomes magnetic when placed in a magnetic field.
what are the magnetic materials
The magnetic elements are iron, nickel and cobalt.
What units are used for current?
amperes or amps (A)
If a wire carrying an electric current is placed in a magnetic field, a force is produced.
The motor effect
The motor effect defenition
The motor effect is when a current-carrying wire experiences a force in a magnetic field.
bar magnet
What units are used for force?
newtons (N)
What is the size of the force acting on a copper wire with a magnetic flux density of 3.6 x 10-2 T acting at right angles to the wire of length 19 m and current of 0.043 A? Round your answer to 2 significant figures.
Would increasing the strength of the magnetic field have an effect on the direction of the force caused by the motor effect?
formula
𝐹=𝐵𝐼𝐿
F=BIL, where:
𝐵=3.6×10−2T
𝐼=0.043A
𝐿=19m
𝐹=0.03N rounded to 2 significant figures.
Would increasing the strength of the magnetic field have an effect on the direction of the force caused by the motor effect?
No, it would not affect the direction of the force. It would only increase the strength of the force.
What is the size of the force acting on a copper wire with a magnetic flux density of 3.6 x 10-2 T acting at right angles to the wire of length 24 m and current of 0.048 A? Give your answer to an appropriate number of significant figures.
0.041 N
A wire is carrying an electric current through a magnetic field. A force on the wire makes it move to the right. In which direction would the wire move if the current in the wire changed direction?
left
When using Fleming’s left-hand rule, the first finger points in the direction of the… what?
The “f” in first finger can stand for field, referring to the magnetic field.
magnetic field
What effect would increasing the strength of the magnetic field have on the force caused by the motor effect?
The stronger the magnetic field, the stronger the force will be.
A wire carries a current of 2A through a magnetic field. The wire experiences a force. What will happen to the size of this force if the current is changed to 1A?
The lower the current, the smaller the force.
The force will be halved.
In a bar magnet we say that like poles do what?
Like poles are the same, and they repel each other.
When using Fleming’s left-hand rule, the thumb points in the direction of the… what?
force
A wire carries a current of 2A through a magnetic field. The wire experiences a force. What will happen to the size of this force if the current is reversed?
Reversing the current will reverse the direction of the force, but not affect the size of the force.
What happens when a brass rod carrying a current is placed at right angles to a magnetic field?
The brass rod carries a current at right angles to the magnetic field, so will experience a force, causing it to move.
Will there be a force on a current-carrying wire in a magnetic field if the current and fields are at right-angles to one another?
yes
The motor effect is strongest when the current-carrying wire and magnetic field lines are at right angles.
When we show the direction of a magnetic field at a certain point, we are showing the direction of the force that would act on a __________ pole placed at that point. What one word completes the sentence?
north
Magnetic field lines always show the force that would act on a north pole.
