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42 Cards in this Set
- Front
- Back
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A charge in a magnetic field feels a force only when it is
a. stationary b. moving c. both |
moving
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A charge moving in a stationary, uniform field will experience a force in which direction?
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Perpendicular to its direction of motion
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In the first right hand rule, what do your fingers represent.
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B
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In the first right hand rule, what does your thumb represent
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Velocity
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In the first right hand rule, what does the palm of your hand represent
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Force on a +q
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A charged particle moves in a straight line through a certain region of space. The magnetic field in that region...
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Has a zero component perpendicular to the particle's velocity
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A long parallel wire carries current in the direction shown. It is in a constant magnetic field directed out of the screen. Which direction is the force on the wire
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Right
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A long parallel wire carries current up. Which direction is the magnetic field produced by this wire at the point to the right of the wire.
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Into the board
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If a moving charge is going the same direction as a current in the wire, which direction will the charge go?
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Towards the wire
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Two long parallel wires carry current in the same direction, what happens to them
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they attract one another
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Two long parallel wires carry current in the opposite direction, what happens to them
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They repel
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If I1= 2 Amps and I2=10 Amps, the force on I1 is _____________ the force on I2
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Equal to
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Two long parallel wires carry current in opposite directions. At a point in the middle the net magnetic field is
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Into the board
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Two long parallel wires carry current in the same direction. At a point in the middle the net magnetic field is . .
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zero
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A simple current loop produces which type of magnetic field?
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Dipole
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If a current carrying wire is turned into a circle with the current moving clockwise, which direction is the magnetic field in the center of the loop
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Into the screen
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If the area of a loop in a magnetic field is increased the magnetic flux through the loop________
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Increases
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The magnetic flux through a loop is maximum when the plane of the loop is _________
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Perpendicular to the magnetic field
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A bar magnet is falling through a loop of wire with constant velocity with the north pole entering first. As the magnet enters the wire, the induced current (as viewed from above):
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Counterclockwise
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A bar magnet is falling through a loop of wire with constant velocity. The north pole enters first. As the magnet leaves the wire, the induced current (as viewed from above):
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Clockwise
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A generator induces current in a loop in a magnetic field by changing the flux through the loop. This is done by
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Changing the orientation of the loop
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Lenz’s law explains the _____ of Faraday’s law.
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the minus sign
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Magnetic field into the board and velocity right...which direction is the force on +q
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up
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A long straight wire carries a steady current (I). A rectangular conducting loop lies in the same plane as the wire, with two sides parallel to the wire and two sides perpendicular. Suppose the loop is pushed toward the wire and I in the wire is to the right, the induced current in the loop is______
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Counterclockwise...it wants to oppose the current in the wire
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Two loops of wire are arranged so that a changing current in one will induce a current in the other. If the current in the first is a constant clockwise current of 1.0 A, the induced current in the second loop will:
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Zero, there is no increase so there is no induction
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Two loops of wire are arranged so that a changing current in one will induce a current in the other. If the current in the first is increasing clockwise by 1.0 A every second, the induced current in the second loop will:
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stay constant but not be zero...it is a steady increase so it is not zero
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What is the symbol for inductor?
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L
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What does an inductor do in a circuit?
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Resists change in current flow
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What is the difference between R and L
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R resists current
L resists change in current |
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In a circuit made up of inductor L, resistance R, ammeter, battery and switch in series, the current is greatest at which of the following times, as measured after the switch is closed?
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The longer the time
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An inductor, battery, resistance, and ammeter and switch are connected in series. If the switch is now closed, what is the current's final value?
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battery voltage divided by resistance
V=IR so I=V/R The inductor does not change this due to the fact that there is no change in current after a short time |
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In a circuit consisting of a resistor connected to an oscillating source of emf (AC) the current reaches its maximum, when voltage is where.
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the same time
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In a circuit consisting of a capacitor connected to an oscillating source of emf (AC) the capacitor . . .
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Continually builds up and discharges
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In an AC current, How does the brightness of the bulb vary as the frequency of the ac source with an inductor is increased from zero?
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Decreases in brightness due to a lot of change
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How does the brightness of the bulb vary as the frequency of the ac source with a capacitor is increased from zero?
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Increases...the capacitor does not have time to charge up and discharge so it does not have time to oppose
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In transmitting electricity from a power plant to the consumer, transformers are utilized for which of the following tasks?
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Stepping up the output voltage at the power plant and
Stepping down the voltage just before it reaches the consumer |
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Why do we use A/C current?
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Because only transformers work with A/C...to induce current there must be a change
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Why do we use Transformers?
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We can use a transformer and step up the voltage so that there is less current and thus less power lost in the lines.
Power output = I ∆V Less current requires high voltage |
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The electric field, E, in an electromagnetic wave is oriented in what direction with respect to its associated magnetic field, B?
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Perpendicular
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How is a electromagnetic wave produced?
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By moving charge up and down in a metal pole (an AC current), an oscillating electric field is produced.
This changing electric field produces a changing magnetic field. These fields are propagated in an electromagnetic wave. |
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The lower the frequency, the _____ the wavelength.
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Longer
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Order of waves in increasing frequency
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Infrared, visible, ultraviolet and gamma
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