Magnetism and Moving Charges - AP Physics 2
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What is the direction of the magnetic field inside a solenoid?
What is the direction of the magnetic field inside a solenoid?
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Parallel to the axis of the solenoid. Field lines run straight through the solenoid's center.
Parallel to the axis of the solenoid. Field lines run straight through the solenoid's center.
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What does Lenz's Law state about electromagnetic induction?
What does Lenz's Law state about electromagnetic induction?
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Induced current opposes the change causing it. Nature opposes changes in magnetic flux through circuits.
Induced current opposes the change causing it. Nature opposes changes in magnetic flux through circuits.
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What is the direction of the magnetic field around a current-carrying wire?
What is the direction of the magnetic field around a current-carrying wire?
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Circular around the wire. Right-hand rule: thumb along current, fingers curl with field.
Circular around the wire. Right-hand rule: thumb along current, fingers curl with field.
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Identify the unit of magnetic flux.
Identify the unit of magnetic flux.
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Weber (Wb). Named after Wilhelm Weber; unit of magnetic flux linkage.
Weber (Wb). Named after Wilhelm Weber; unit of magnetic flux linkage.
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What is the formula for the Lorentz force?
What is the formula for the Lorentz force?
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$F = q(E + v \times B)$. Combines electric and magnetic forces on a moving charge.
$F = q(E + v \times B)$. Combines electric and magnetic forces on a moving charge.
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State the effect of a uniform magnetic field on the speed of a charged particle.
State the effect of a uniform magnetic field on the speed of a charged particle.
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Speed remains constant. Magnetic force is perpendicular to velocity, doing no work.
Speed remains constant. Magnetic force is perpendicular to velocity, doing no work.
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Define the term 'magnetic flux'.
Define the term 'magnetic flux'.
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Product of magnetic field and area normal to it. Measures how much magnetic field passes through a surface.
Product of magnetic field and area normal to it. Measures how much magnetic field passes through a surface.
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Calculate the magnetic field at a point $5cm$ from a wire carrying $6A$ current.
Calculate the magnetic field at a point $5cm$ from a wire carrying $6A$ current.
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$2.4 \times 10^{-5} , T$. Using $B = \frac{\mu_0 I}{2\pi r}$ with given values.
$2.4 \times 10^{-5} , T$. Using $B = \frac{\mu_0 I}{2\pi r}$ with given values.
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Define the unit of magnetic field strength.
Define the unit of magnetic field strength.
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Tesla (T). Named after Nikola Tesla; measures magnetic field intensity.
Tesla (T). Named after Nikola Tesla; measures magnetic field intensity.
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State the effect of a uniform magnetic field on the speed of a charged particle.
State the effect of a uniform magnetic field on the speed of a charged particle.
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Speed remains constant. Magnetic force is perpendicular to velocity, doing no work.
Speed remains constant. Magnetic force is perpendicular to velocity, doing no work.
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What is the formula for the Lorentz force?
What is the formula for the Lorentz force?
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$F = q(E + v \times B)$. Combines electric and magnetic forces on a moving charge.
$F = q(E + v \times B)$. Combines electric and magnetic forces on a moving charge.
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Find the magnetic force on a $2C$ charge moving at $3m/s$ in a $4T$ field at $90^{\circ}$.
Find the magnetic force on a $2C$ charge moving at $3m/s$ in a $4T$ field at $90^{\circ}$.
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$24 , N$. Using $F = qvB$: $2 \times 3 \times 4 = 24N$ at maximum angle.
$24 , N$. Using $F = qvB$: $2 \times 3 \times 4 = 24N$ at maximum angle.
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Define the term 'magnetic flux'.
Define the term 'magnetic flux'.
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Product of magnetic field and area normal to it. Measures how much magnetic field passes through a surface.
Product of magnetic field and area normal to it. Measures how much magnetic field passes through a surface.
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What is the force between two parallel current-carrying wires?
What is the force between two parallel current-carrying wires?
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Attractive if currents are in the same direction. Parallel currents attract; antiparallel currents repel each other.
Attractive if currents are in the same direction. Parallel currents attract; antiparallel currents repel each other.
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What is the effect of a magnetic field on a loop of current?
What is the effect of a magnetic field on a loop of current?
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Torque acts on the loop. Current loop behaves like magnetic dipole in external field.
Torque acts on the loop. Current loop behaves like magnetic dipole in external field.
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What is the formula for magnetic flux?
What is the formula for magnetic flux?
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$\Phi = B \cdot A \cdot \cos(\theta)$. Flux depends on field strength, area, and angle between them.
$\Phi = B \cdot A \cdot \cos(\theta)$. Flux depends on field strength, area, and angle between them.
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Identify the condition for maximum magnetic force on a charge.
Identify the condition for maximum magnetic force on a charge.
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$\theta = 90^{\circ}$. Perpendicular alignment gives maximum $\sin(\theta) = 1$.
$\theta = 90^{\circ}$. Perpendicular alignment gives maximum $\sin(\theta) = 1$.
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What is the Hall effect?
What is the Hall effect?
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Voltage developed across a conductor in a magnetic field. Moving charges in magnetic field separate, creating potential difference.
Voltage developed across a conductor in a magnetic field. Moving charges in magnetic field separate, creating potential difference.
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Define the term 'magnetic dipole moment'.
Define the term 'magnetic dipole moment'.
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Measure of the strength of a magnetic source. Quantifies the magnetic field strength produced by a current distribution.
Measure of the strength of a magnetic source. Quantifies the magnetic field strength produced by a current distribution.
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What is the path of a charged particle in a uniform magnetic field?
What is the path of a charged particle in a uniform magnetic field?
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Circular or helical. Magnetic force provides centripetal acceleration for curved motion.
Circular or helical. Magnetic force provides centripetal acceleration for curved motion.
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Calculate the magnetic force on a $3m$ wire carrying $5A$ in a $0.2T$ field.
Calculate the magnetic force on a $3m$ wire carrying $5A$ in a $0.2T$ field.
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$3 , N$. Using $F = ILB$: $5 \times 3 \times 0.2 = 3N$.
$3 , N$. Using $F = ILB$: $5 \times 3 \times 0.2 = 3N$.
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State the Biot-Savart Law for the magnetic field due to a current element.
State the Biot-Savart Law for the magnetic field due to a current element.
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$dB = \frac{\mu_0 I dl \sin(\theta)}{4\pi r^2}$. Fundamental law relating current elements to magnetic field production.
$dB = \frac{\mu_0 I dl \sin(\theta)}{4\pi r^2}$. Fundamental law relating current elements to magnetic field production.
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What is the effect of a magnetic field on a stationary charge?
What is the effect of a magnetic field on a stationary charge?
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No force is exerted. Magnetic force requires motion; stationary charges are unaffected.
No force is exerted. Magnetic force requires motion; stationary charges are unaffected.
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Calculate the magnetic force on a $0.5C$ charge at rest in a $2T$ field.
Calculate the magnetic force on a $0.5C$ charge at rest in a $2T$ field.
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$0 , N$. No velocity means no magnetic force on the charge.
$0 , N$. No velocity means no magnetic force on the charge.
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Calculate the magnetic field at a point $5cm$ from a wire carrying $6A$ current.
Calculate the magnetic field at a point $5cm$ from a wire carrying $6A$ current.
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$2.4 \times 10^{-5} , T$. Using $B = \frac{\mu_0 I}{2\pi r}$ with given values.
$2.4 \times 10^{-5} , T$. Using $B = \frac{\mu_0 I}{2\pi r}$ with given values.
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What is the value of $\mu_0$, the permeability of free space?
What is the value of $\mu_0$, the permeability of free space?
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$4\pi \times 10^{-7} , T\cdot m/A$. Fundamental physical constant used in magnetic field calculations.
$4\pi \times 10^{-7} , T\cdot m/A$. Fundamental physical constant used in magnetic field calculations.
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What is the relationship between electric and magnetic fields in electromagnetic waves?
What is the relationship between electric and magnetic fields in electromagnetic waves?
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Perpendicular to each other. EM waves consist of oscillating $E$ and $B$ fields at right angles.
Perpendicular to each other. EM waves consist of oscillating $E$ and $B$ fields at right angles.
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What is the formula for the magnetic force on a moving charge?
What is the formula for the magnetic force on a moving charge?
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$F = qvB , \sin(\theta)$. Force depends on charge, velocity, field strength, and angle between $v$ and $B$.
$F = qvB , \sin(\theta)$. Force depends on charge, velocity, field strength, and angle between $v$ and $B$.
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Define Ampère's Law.
Define Ampère's Law.
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Line integral of $B$ around a closed path equals $\mu_0 I$. Relates magnetic field circulation to enclosed current.
Line integral of $B$ around a closed path equals $\mu_0 I$. Relates magnetic field circulation to enclosed current.
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What does a solenoid generate when a current flows through it?
What does a solenoid generate when a current flows through it?
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Uniform magnetic field inside. Coil of wire creates strong, uniform field along its axis.
Uniform magnetic field inside. Coil of wire creates strong, uniform field along its axis.
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