Term
| Magnets have two ends called ? |
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Definition
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Term
Like poles ______
unlike poles _______ |
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Definition
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Term
| Magnetic fields can be visualized using _____ which are always _______ |
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Definition
1.magnetic field lines
2.closed loops |
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Term
| magnetic field lines always go from ____ to ____ |
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Definition
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Term
True or False: the Earth’s “North Pole” is really a south magnetic pole |
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Definition
True:
the north ends of magnets are attracted to it. |
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Term
| A uniform magnetic field is constant in (2) |
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Definition
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Term
| Experiment shows that an ______ produces a magnetic field |
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Definition
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Term
Given that Electric Currents Produce Magnetic Fields, what rule can we use to the find the direction of the magnetic field? |
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Definition
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Term
| A magnet exerts _____ on a current-carrying wire. The direction of the force is given by a right-hand rule |
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Definition
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Term
| the Force on an Electric Current carring wire due to a Magnetic Field, formula |
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Definition
F= IlB sin θ
this means the force on the wire depends on:
the current (I),
the length of the wire (l),
the magnetic field (B)
its orientation . |
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Term
| If the direction of I is perpendicular to B, then θ is? sin θ ? |
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Definition
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Term
| If I (the current) is parallel or antiparallel to B, then θ= ____ and sin θ = ____. |
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Definition
θ = 0˚
sin θ = 0
This equation defines the magnetic field B.
the force is zero |
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Term
| Magnetic Field, Unit of B |
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Definition
the tesla, T.
1 T = 1 N/A·m.
Another unit sometimes used: the gauss (G).
1 G = 10-4T. |
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Term
| The direction of a force on a electric current in a magnetic field is always |
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Definition
perpendicular to the direction:
of the current & magnetic field |
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Term
| if the magnetic field is stronger then the force will be ____ |
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Definition
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Term
True or False: b/c a current carrying wire experiences a force when placed in an electric field,
1.can moving charged particles not in a wire experience a force when moving through a magnetic field?
2.When is this force the greatest? |
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Definition
1.yes
2. when the particle moves perpendicular to the electric field (B)
θ= 90 |
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Term
| A moving charge feels a force of zero when? |
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Definition
when the particle moves parallel to the magnetic field lines
θ = 0 |
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Term
| A negative charge -Q is placed at rest near a magnet. Will the charge begin to move? Will it feel a force? What if the charge were positive, +Q? |
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Definition
No to all questions.
A charge at rest has a velocity of zero. Magnetic fields excert a force only on moving electric charges |
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Term
| The force on a moving charge : formula |
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Definition
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Term
| If a charged particle (electron or proton) is moving perpendicular to a uniform magnetic field, its path will be? |
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Definition
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Term
| What is the path of a charged particle if its velocity is not perpendicular to the magnetic field? |
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Definition
The parallel component of v experiences no force, so it remains constant. The perpendicular component of v results in circular motion.
Together this produces a spiral motion. |
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Term
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Definition
Charged ions that approach the Earth from the sun (solar wind) and are drawn toward the poles.
This causes the Northern lights. |
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Term
Magnetic Field Due to a Long Straight Wire:
the magnetic field strenghth is greatest at a given point when |
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Definition
| if the current flowing in the wire was greater |
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Term
Magnetic Field Due to a Long Straight Wire:
the magnetic field strenghth is weaker at points |
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Definition
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Term
Force between Two Parallel Wires :
Parallel currents _____ antiparallel currents ___
attract or repel |
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Definition
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Term
Solenoids and Electromagnets:
If a piece of iron is inserted in the solenoid, the magnetic field (increases or decreases)? |
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Definition
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Term
| How does a solenoid work? |
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Definition
- a solenoid is a long coil of wire with many loops.
- each loop produces a magnetic field and the total field in the solenoid will be the sum of the fields due to each current of each loop.
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Term
| Describe the magnetic field inside the solenoid if it contains a large number of loops and are closed packed? |
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Definition
| the magnetic field is nearly constant. |
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Term
| Describe the magnetic field outside the solenoid |
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Definition
| the field lines spread out in space, so the magnetic field is much weaker outside the solenoid than inside the solenoid. |
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