Question 1

Two current-carrying wires produce a repulsive force of magnitude F₀ when the wires are separated by a distance of r₀. If the current is doubled in each wire while the distance between the two wires is changed to 2r₀, a force results with a magnitude of A) (1/2)F₀. B) F₀. C) 2F₀. D) 4F₀.

Accepted Answer

The answer of Two current-carrying wires produce a repulsive force...

Question 2

The SI unit associate with the magnetic moment$\mu$, is A) ampere·m². B) ampere/m². C) ampere²·m. D) ampere²/m².

Accepted Answer

The correct SI unit for magnetic moment is ampere·meter squared (ampere·m^2), which matches choice A.

Question 3

A loop of wire has an area of 0.10 m² and carries 15 mA of current. The magnetic moment of the loop is A) 0.001 A·m². B) 0.15 A/m². C) 71 *10^-5 A²/m. D) 2.25 A²/m².

Accepted Answer

The magnetic moment ($ \mu $) of a current loop is given by the product of the current (I) and the area (A) of the loop, $\mu = I \times A$. Given that the area is $0.10 \, \text{m}^2$ and the current is $15 \, \text{mA} = 0.015 \, \text{A}$, the magnetic moment is $0.015 \, \text{A} \times 0.10 \, \text{m}^2 = 0.0015 \, \text{A}\cdot\text{m}^2$, which is closest to option A, considering a possible typo in the options.

Question 4

The maximum torque of a 100-turn loop of wire that has an area of 0.15 m² and is carrying 1.5 A of current in a uniform magnetic field of 2.0 T is A) zero. B) 5.0 N·m. C) 15 N·m. D) 45 N·m.

Accepted Answer

The maximum torque (τ) on a current loop in a magnetic field is given by τ = n * I * A * B, where n is the number of turns, I is the current, A is the area, and B is the magnetic field. Substituting the given values: τ = 100 * 1.5 * 0.15 * 2.0 = 45 N·m.

Question 5

A 100-turn loop of wire whose area is 0.15 m² carries 3.0 A of current. If a uniform magnetic field of 2.0 T makes an angle of 60° with the plane of the loop, the maximum torque on the loop is A) zero. B) 5.0 N·m. C) 15 N·m. D) 45 N·m.

Accepted Answer

The answer of A 100-turn loop of wire whose area...

Question 6

A rectangular loop of wire whose dimensions are 15 cm * 25 cm carries a current of 5.0 A. The loop is in a uniform magnetic field of 1.5 T whose direction is parallel to the plane of the loop. The torque acting on the loop is
A) zero.
B) 0.24 N·m.
C) 0.28 N·m.
D) 0.35 N·m.

Accepted Answer

The answer of A rectangular loop of wire whose dimensions...

Question 7

A rectangular loop of wire whose dimensions are 15 cm * 25 cm carries a current of 5.0 A. The loop is in a uniform magnetic field of 1.5 T whose direction is perpendicular to the plane of the loop. The torque acting on the loop is
A) zero.
B) 0.24 N·m.
C) 0.28 N·m.
D) 0.35 N·m.

Accepted Answer

The torque on a loop in a magnetic field is given by τ = nIABsinθ. Here, θ = 90° (since the field is perpendicular), so sinθ = 1. The area A = 0.15 m * 0.25 m = 0.0375 m². Thus, τ = 1 * 5.0 A * 0.0375 m² * 1.5 T * 1 = 0.28125 N·m. However, since the field is perpendicular, the torque is zero.

Question 8

The magnitude of the torque produced by a magnetic moment $\mu$ = 2.0 (2i + j) A·m² in a magnetic field given by 1.5 (i + 4k) mT is A) zero. B) 3 mN·m. C) 9 mN·m. D) 27 mN·m.

Accepted Answer

The answer of The magnitude of the torque produced by...

Question 9

The magnitude of the torque produced by a magnetic moment $\mu$ = 2.0 (2i + j) A·m² in a magnetic field given by 1.5 (i + k) mT is A) 3.0 (i - 2j - 2k) mN·m. B) 9.0 mN·m. C) 3(-i + 2j - 2k) mN·m. D) zero.

Accepted Answer

The torque is given by $\tau = \mu \times B$, where $\mu$ is the magnetic moment and B is the magnetic field. In this case, $\mu = 2.0 (2i + j) A·m^2$ and B = 1.5 (i + k) mT. So,$$\tau = 2.0 (2i + j) A·m^2 \times 1.5 (i + k) mT$$$$= 3.0 (2i - j - 2k) mN·m$$

Question 10

The potential energy of a magnetic moment $\mu$ = 1.0 (2i + j) A·m² in a magnetic field given by 1.5 (2i + k) mT is A) -6.0 mJ. B) -3.0 mJ. C) 3.0 mJ. D) -1.5 mJ.

Accepted Answer

The potential energy of a magnetic moment in a magnetic field is given by U = -μ·B. In this case, μ = 1.0 (2i + j) A·m2 and B = 1.5 (2i + k) mT. So, U = -1.0 (2i + j) A·m2 · 1.5 (2i + k) mT = -3.0 (2i + j) mJ.

Question 11

The potential energy of a magnetic moment $\mu$ = 1.0 (-2i + j + k) A·m² in a magnetic field given by 1.5 (i + j + k)mT is A) zero. B) -3.0 mJ. C) 3.0 mJ. D) -1.5 mJ.

Accepted Answer

The answer of The potential energy of a magnetic moment...

Question 12

The maximum energy difference between the parallel and antiparallel configurations produced by a magnetic moment whose magnitude is $\mu$ = 2.0 A·m² in a magnetic field given by 1.5 mT is A) zero. B) 1.5 mJ. C) 3.0 mJ. D) 6.0 mJ.

Accepted Answer

The answer of The maximum energy difference between the parallel...

Question 13

The SI units associated with magnetic susceptibility are A) A/m². B) T/m². C) T·m. D) Hold on; the magnetic susceptibility is dimensionless.

Accepted Answer

Magnetic susceptibility is a dimensionless quantity, indicating it has no units. It is a measure of how much a material will become magnetized in an applied magnetic field.

Question 14

Materials with a small positive magnetic susceptibility are called
A) paramagnets.
B) diamagnets.
C) ferromagnets.
D) permanent magnets.

Accepted Answer

Paramagnets are materials that exhibit a small positive magnetic susceptibility, meaning they are weakly attracted by the poles of a magnet but do not retain magnetic properties when the external field is removed.

Question 15

Materials with a small negative magnetic susceptibility are called
A) paramagnets.
B) diamagnets.
C) ferromagnets.
D) permanent magnets.

Accepted Answer

Diamagnets are materials with a small negative magnetic susceptibility, meaning they are repelled by magnetic fields.

Question 16

The SI units associated with magnetic permeability are A) N·s/C. B) N·s²/C. C) N·s²/C². D) Hold on; the magnetic permeability is dimensionless.

Accepted Answer

The answer of The SI units associated with magnetic permeability...

Question 17

For a magnetic material the ratio of the magnetic permeability to the permeability of free space is 3. The ratio of the B_matter/B_external for this material is A) zero. B) 2 C) 3 D) 4

Accepted Answer

The answer of For a magnetic material the ratio of...

Question 18

For a magnetic material the ratio of the magnetic permeability to the permeability of free space is 11. The material is placed in a uniform magnetic field of strength 1.0 mT. The magnetic field produced in the material is approximately
A) 11 mT.
B) 10 mT.
C) 1.2 mT.
D) 1.0 mT.

Accepted Answer

The answer of For a magnetic material the ratio of...

Question 19

A Hall voltage is measured across the width of two rods under the same experimental conditions. The only variation is that the width of the second rod is twice that of the first rod. The Hall voltage across the second rod will be
A) twice the value measured across the first rod.
B) half of the value measured across the first rod.
C) one-quarter the value measured across the first rod.
D) Hold on; the value of the voltage will not change.

Accepted Answer

The Hall voltage (V_H) is given by V_H = (IB)/(net), where I is the current, B is the magnetic field, n is the charge carrier density, e is the charge of an electron, and t is the thickness of the conductor (which can be considered analogous to the width in this context). Since the width of the rod does not appear in this formula, changing the width while keeping other parameters constant does not affect the Hall voltage.

Question 20

A Hall voltage is measured across the width of two rods under the same experimental conditions. The only variation is that the thickness of the second rod is twice that of the first rod. The Hall voltage across the second rod will be
A) twice the value measured across the first rod.
B) half of the value measured across the first rod.
C) one-quarter the value measured across the first rod.
D) Hold on; the value of the voltage will not change.

Accepted Answer

The Hall voltage is inversely proportional to the thickness of the conductor. If the thickness of the second rod is twice that of the first, the Hall voltage will be half.

Quiz 30: Charges and Currents in Magnetic Fields

Two current-carrying wires produce a repulsive force of magnitude F₀ when the wires are separated by a distance of r₀. If the current is doubled in each wire while the distance between the two wires is changed to 2r₀, a force results with a magnitude of

The SI unit associate with the magnetic moment $\mu$ , is

A loop of wire has an area of 0.10 m² and carries 15 mA of current. The magnetic moment of the loop is

The maximum torque of a 100-turn loop of wire that has an area of 0.15 m² and is carrying 1.5 A of current in a uniform magnetic field of 2.0 T is

A 100-turn loop of wire whose area is 0.15 m² carries 3.0 A of current. If a uniform magnetic field of 2.0 T makes an angle of 60° with the plane of the loop, the maximum torque on the loop is

A rectangular loop of wire whose dimensions are 15 cm * 25 cm carries a current of 5.0 A. The loop is in a uniform magnetic field of 1.5 T whose direction is parallel to the plane of the loop. The torque acting on the loop is

A rectangular loop of wire whose dimensions are 15 cm * 25 cm carries a current of 5.0 A. The loop is in a uniform magnetic field of 1.5 T whose direction is perpendicular to the plane of the loop. The torque acting on the loop is

The magnitude of the torque produced by a magnetic moment $\mu$ = 2.0 (2i + j) A·m² in a magnetic field given by 1.5 (i + 4k) mT is

The magnitude of the torque produced by a magnetic moment $\mu$ = 2.0 (2i + j) A·m² in a magnetic field given by 1.5 (i + k) mT is

The potential energy of a magnetic moment $\mu$ = 1.0 (2i + j) A·m² in a magnetic field given by 1.5 (2i + k) mT is

The potential energy of a magnetic moment $\mu$ = 1.0 (-2i + j + k) A·m² in a magnetic field given by 1.5 (i + j + k) mT is

The maximum energy difference between the parallel and antiparallel configurations produced by a magnetic moment whose magnitude is $\mu$ = 2.0 A·m² in a magnetic field given by 1.5 mT is

The SI units associated with magnetic susceptibility are

Materials with a small positive magnetic susceptibility are called

Materials with a small negative magnetic susceptibility are called

The SI units associated with magnetic permeability are

For a magnetic material the ratio of the magnetic permeability to the permeability of free space is 3. The ratio of the B_matter/B_external for this material is

For a magnetic material the ratio of the magnetic permeability to the permeability of free space is 11. The material is placed in a uniform magnetic field of strength 1.0 mT. The magnetic field produced in the material is approximately

A Hall voltage is measured across the width of two rods under the same experimental conditions. The only variation is that the width of the second rod is twice that of the first rod. The Hall voltage across the second rod will be

A Hall voltage is measured across the width of two rods under the same experimental conditions. The only variation is that the thickness of the second rod is twice that of the first rod. The Hall voltage across the second rod will be

Quiz 30: Charges and Currents in Magnetic Fields

Two current-carrying wires produce a repulsive force of magnitude F0 when the wires are separated by a distance of r0. If the current is doubled in each wire while the distance between the two wires is changed to 2r0, a force results with a magnitude of

The SI unit associate with the magnetic moment μ\muμ , is

A loop of wire has an area of 0.10 m2 and carries 15 mA of current. The magnetic moment of the loop is

The maximum torque of a 100-turn loop of wire that has an area of 0.15 m2 and is carrying 1.5 A of current in a uniform magnetic field of 2.0 T is

A 100-turn loop of wire whose area is 0.15 m2 carries 3.0 A of current. If a uniform magnetic field of 2.0 T makes an angle of 60° with the plane of the loop, the maximum torque on the loop is