Magnetism and Current-Carrying Wires - 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. Solenoid creates uniform field along its central axis.
Parallel to the axis. Solenoid creates uniform field along its central axis.
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Find the magnetic dipole moment of a $10$-turn coil with $2 \text{ A}$ current and $0.5 \text{ m}^2$ area.
Find the magnetic dipole moment of a $10$-turn coil with $2 \text{ A}$ current and $0.5 \text{ m}^2$ area.
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$10 \text{ A m}^2$. Use $\mu = NIA$ with $N=10$, $I=2 \text{A}$, $A=0.5 \text{m}^2$.
$10 \text{ A m}^2$. Use $\mu = NIA$ with $N=10$, $I=2 \text{A}$, $A=0.5 \text{m}^2$.
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What happens to the magnetic field strength if the current in a wire doubles?
What happens to the magnetic field strength if the current in a wire doubles?
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Doubles. Magnetic field is directly proportional to current.
Doubles. Magnetic field is directly proportional to current.
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What is the effect on the magnetic field if the number of turns in a solenoid is doubled?
What is the effect on the magnetic field if the number of turns in a solenoid is doubled?
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Doubles. Field strength is directly proportional to number of turns.
Doubles. Field strength is directly proportional to number of turns.
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What is the magnetic force direction on a wire with current in a magnetic field?
What is the magnetic force direction on a wire with current in a magnetic field?
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Perpendicular to both current and field. Force follows right-hand rule for current and field vectors.
Perpendicular to both current and field. Force follows right-hand rule for current and field vectors.
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What is the direction of the force on a negative charge in a magnetic field?
What is the direction of the force on a negative charge in a magnetic field?
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Opposite to right-hand rule. Negative charge reverses the force direction from right-hand rule.
Opposite to right-hand rule. Negative charge reverses the force direction from right-hand rule.
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Calculate the magnetic force on a $2 \text{ C}$ charge moving at $3 \text{ m/s}$ perpendicular to a $4 \text{ T}$ field.
Calculate the magnetic force on a $2 \text{ C}$ charge moving at $3 \text{ m/s}$ perpendicular to a $4 \text{ T}$ field.
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$24$ N. Use $F = qvB$ with perpendicular motion and field.
$24$ N. Use $F = qvB$ with perpendicular motion and field.
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What is the direction of the magnetic force on a positive charge moving in a magnetic field?
What is the direction of the magnetic force on a positive charge moving in a magnetic field?
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Right-hand rule. Point fingers in velocity direction, curl toward field, thumb shows force.
Right-hand rule. Point fingers in velocity direction, curl toward field, thumb shows force.
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State the unit of magnetic field strength.
State the unit of magnetic field strength.
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Tesla (T). Tesla is the SI unit for magnetic field strength.
Tesla (T). Tesla is the SI unit for magnetic field strength.
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What is the effect of temperature on the magnetization of ferromagnetic materials?
What is the effect of temperature on the magnetization of ferromagnetic materials?
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Decreases with increasing temperature. Higher temperature reduces magnetic alignment in ferromagnets.
Decreases with increasing temperature. Higher temperature reduces magnetic alignment in ferromagnets.
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Determine the force on a $1.5 \text{ m}$ wire with $4 \text{ A}$ current parallel to a $0.2 \text{ T}$ field.
Determine the force on a $1.5 \text{ m}$ wire with $4 \text{ A}$ current parallel to a $0.2 \text{ T}$ field.
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$0$ N. Parallel orientation gives $\sin(0°) = 0$, so no force.
$0$ N. Parallel orientation gives $\sin(0°) = 0$, so no force.
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What is the relationship between magnetic field strength and distance from a wire?
What is the relationship between magnetic field strength and distance from a wire?
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Inversely proportional. Field strength decreases as $\frac{1}{r}$ from the wire.
Inversely proportional. Field strength decreases as $\frac{1}{r}$ from the wire.
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What is the magnetic field direction around a long straight current-carrying wire?
What is the magnetic field direction around a long straight current-carrying wire?
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Circular around the wire. Current creates concentric circular field lines around the wire.
Circular around the wire. Current creates concentric circular field lines around the wire.
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Calculate the force between two parallel wires $2 \text{ m}$ apart carrying $4 \text{ A}$ each.
Calculate the force between two parallel wires $2 \text{ m}$ apart carrying $4 \text{ A}$ each.
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$1.6 \times 10^{-6}$ N. Use force formula with $d=2m$ and $I_1=I_2=4A$.
$1.6 \times 10^{-6}$ N. Use force formula with $d=2m$ and $I_1=I_2=4A$.
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What is the effect of doubling the velocity of a charged particle on the magnetic force it experiences?
What is the effect of doubling the velocity of a charged particle on the magnetic force it experiences?
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Doubles the force. Force is directly proportional to particle velocity.
Doubles the force. Force is directly proportional to particle velocity.
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State the Biot-Savart Law for a small segment of current-carrying wire.
State the Biot-Savart Law for a small segment of current-carrying wire.
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$dB = \frac{\mu_0}{4\pi} \frac{I , d\ell \times \hat{r}}{r^2}$. Fundamental law for calculating magnetic fields from current elements.
$dB = \frac{\mu_0}{4\pi} \frac{I , d\ell \times \hat{r}}{r^2}$. Fundamental law for calculating magnetic fields from current elements.
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State the formula for the magnetic field inside a solenoid.
State the formula for the magnetic field inside a solenoid.
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$B = \mu_0 n I$. Field depends on turns per length and current.
$B = \mu_0 n I$. Field depends on turns per length and current.
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What is the effect of a magnetic field on an electron at rest?
What is the effect of a magnetic field on an electron at rest?
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No effect. Magnetic force requires motion of charged particle.
No effect. Magnetic force requires motion of charged particle.
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What is the torque on a current loop in a uniform magnetic field?
What is the torque on a current loop in a uniform magnetic field?
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$\tau = \mu B \sin(\theta)$. Torque depends on magnetic moment and field angle.
$\tau = \mu B \sin(\theta)$. Torque depends on magnetic moment and field angle.
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Determine the magnetic force on a $0.5 \text{ C}$ charge moving at $4 \text{ m/s}$ in a $1 \text{ T}$ field.
Determine the magnetic force on a $0.5 \text{ C}$ charge moving at $4 \text{ m/s}$ in a $1 \text{ T}$ field.
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$2$ N. Use $F = qvB$ with $q=0.5C$, $v=4m/s$, $B=1T$.
$2$ N. Use $F = qvB$ with $q=0.5C$, $v=4m/s$, $B=1T$.
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Find the magnetic field at the center of a loop with $5 \text{ A}$ and radius $0.1 \text{ m}$.
Find the magnetic field at the center of a loop with $5 \text{ A}$ and radius $0.1 \text{ m}$.
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$10^{-5}$ T. Use $B = \frac{\mu_0 I}{2R}$ with given values.
$10^{-5}$ T. Use $B = \frac{\mu_0 I}{2R}$ with given values.
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What fundamental quantity creates a magnetic field in a wire?
What fundamental quantity creates a magnetic field in a wire?
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Electric current. Moving charges (current) generate magnetic fields.
Electric current. Moving charges (current) generate magnetic fields.
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Determine the magnetic force on a $1 \text{ C}$ charge moving at $2 \text{ m/s}$ in a $3 \text{ T}$ field.
Determine the magnetic force on a $1 \text{ C}$ charge moving at $2 \text{ m/s}$ in a $3 \text{ T}$ field.
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$6$ N. Use $F = qvB$ with $q=1C$, $v=2m/s$, $B=3T$.
$6$ N. Use $F = qvB$ with $q=1C$, $v=2m/s$, $B=3T$.
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What is the magnetic force on a charged particle moving parallel to a magnetic field?
What is the magnetic force on a charged particle moving parallel to a magnetic field?
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Zero. No perpendicular component means no magnetic force.
Zero. No perpendicular component means no magnetic force.
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Identify the relationship between current direction and magnetic field in a wire.
Identify the relationship between current direction and magnetic field in a wire.
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Right-hand grip rule. Curl fingers in current direction, thumb points along magnetic field.
Right-hand grip rule. Curl fingers in current direction, thumb points along magnetic field.
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What is the formula for the magnetic force on a current-carrying wire?
What is the formula for the magnetic force on a current-carrying wire?
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$F = I L B , \sin(\theta)$. Force equals current times length times magnetic field times sine of angle.
$F = I L B , \sin(\theta)$. Force equals current times length times magnetic field times sine of angle.
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Calculate the magnetic force on a wire with $3 \text{ A}$ current and $1 \text{ m}$ length in a $2 \text{ T}$ field.
Calculate the magnetic force on a wire with $3 \text{ A}$ current and $1 \text{ m}$ length in a $2 \text{ T}$ field.
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$6$ N. Use $F = ILB$ with perpendicular orientation.
$6$ N. Use $F = ILB$ with perpendicular orientation.
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State the formula for the force between two parallel current-carrying wires.
State the formula for the force between two parallel current-carrying wires.
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$F = \frac{\mu_0 I_1 I_2 L}{2 \pi d}$. Force per unit length between parallel wires carrying current.
$F = \frac{\mu_0 I_1 I_2 L}{2 \pi d}$. Force per unit length between parallel wires carrying current.
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State the formula for the magnetic dipole moment of a coil.
State the formula for the magnetic dipole moment of a coil.
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$\mu = NIA$. Product of turns, current, and loop area.
$\mu = NIA$. Product of turns, current, and loop area.
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State the formula for the magnetic field due to a moving point charge.
State the formula for the magnetic field due to a moving point charge.
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$B = \frac{\mu_0 q v \times \hat{r}}{4 \pi r^2}$. Moving charge creates magnetic field like current element.
$B = \frac{\mu_0 q v \times \hat{r}}{4 \pi r^2}$. Moving charge creates magnetic field like current element.
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