Question 1

The diagram shows two small paramagnetic spheres, one near each end of a bar magnet.Which of the following statements is true?

Accepted Answer

The answer of The diagram shows two small paramagnetic spheres,...

Question 2

If an electron has zero orbital angular momentum, the magnitude of its magnetic dipole moment equals:

Accepted Answer

The answer of If an electron has zero orbital angular...

Question 3

A paramagnetic substance is placed in a weak magnetic field and its absolute temperature T is increased.As a result, its magnetization:

Accepted Answer

Paramagnetic substances follow Curie's law, which states that the magnetization of the material is inversely proportional to its temperature. Therefore, as the temperature increases, the magnetization decreases in proportion to 1/T.

Question 4

The soft iron core in the solenoid shown is removable.Then:

Accepted Answer

The answer of The soft iron core in the solenoid...

Question 5

Magnetization is:

Accepted Answer

Magnetization is defined as the magnetic dipole moment per unit volume of an object, representing how much magnetic moment is present in a given volume of material.

Question 6

An electron in a hydrogen atom moves in a circle of radius 1.1 x 10^-1⁰ m at a speed of about 1.6 x 10⁶ m/s.What is the magnetic dipole moment of this electron due to its orbital motion?

Accepted Answer

The magnetic dipole moment due to orbital motion is given by μ = IA, where I is the current or the rate of charge flow and A is the area of the circular loop. Using the equation for centripetal force, F = mv²/r, we can find the current as I = ev/2πr, where e is the charge of the electron. Substituting this in the expression for μ, we get μ = (e/2m)(vr²) = (e/2m)(1.1 x 10^-10 m)(1.6 x 10^6 m/s)^2 = 1.41 x 10^-23 J/T. The correct answer is therefore B, 1.4 x 10^-23 J/T.

Question 7

A magnetic field  is applied to a diamagnetic substance.In the interior the magnetic field produced by the magnetic dipoles of the substance is:

Accepted Answer

Diamagnetic substances have magnetic dipoles that are induced in the opposite direction to the applied magnetic field. Therefore, the magnetic field produced by the dipoles in the substance is less than the applied magnetic field and in the opposite direction.

Question 8

If an electron has an orbital angular momentum with magnitude L the magnitude of the orbital contribution to its magnetic dipole moment is given by:

Accepted Answer

The magnitude of the orbital contribution to the electron's magnetic dipole moment is given by μ = (e/2m)L, where e is the charge of the electron, m is its mass, and L is the magnitude of its orbital angular momentum. Therefore, the correct choice is B.

Question 9

The diagram shows the spin angular momentum vectors of two electrons and two protons in the same external magnetic field.The field points upward in the diagram.Rank the situations according to the potential energy, least to greatest.

Accepted Answer

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Question 10

A paramagnetic substance, in an external magnetic field, is thermally isolated.The field is then removed.As a result:

Accepted Answer

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Question 11

Lenz' law can explain:

Accepted Answer

Lenz's law is related to the induction of currents that oppose changes in magnetic fields, which is a characteristic of diamagnetism. It does not directly explain paramagnetism or ferromagnetism.

Question 12

What are the possible allowed values of the orbital magnetic quantum number m_ℓ of the electron?

Accepted Answer

The orbital magnetic quantum number, denoted as $m_l$, can take on values from $-l$ to $+l$ in integer steps, where $l$ is the azimuthal (or angular momentum) quantum number. This means for a given $l$, $m_l$ can be 0, ±1, ±2, …, up to $l$. This allows for a range of values depending on the orbital in question, making option D correct.

Question 13

The magnitude of the Bohr magneton is about:

Accepted Answer

The Bohr magneton is approximately 9.274 x 10^-24 J/T, which is closest to 10^-23 J/T.

Question 14

The units of magnetization are:

Accepted Answer

The units of magnetization are measured in terms of Ampere/meter, which represents the magnitude of magnetic moment per unit volume.

Question 15

A magnetic field  is applied to a paramagnetic substance.In the interior the magnetic field produced by the magnetic dipoles of the substance is:

Accepted Answer

The answer of A magnetic field  is applied to...

Question 16

Paramagnetism is closely associated with:

Accepted Answer

Paramagnetism is the tendency of materials to become weakly magnetic in the presence of an external magnetic field. This is due to the alignment of electron dipole moments with the applied magnetic field. In paramagnetic materials, the electron spins are randomly oriented in the absence of an external magnetic field, but when a field is applied, the spins tend to align in the direction of the field, resulting in a net magnetic moment.

Question 17

If  is the orbital angular momentum of an electron, the magnetic dipole moment associated with its orbital motion:

Accepted Answer

The answer of If  is the orbital angular momentum...

Question 18

The magnetic dipole moment of an atomic electron is typically:

Accepted Answer

The magnetic dipole moment of an atomic electron is typically a few Bohr magnetons, which is due to the electron spinning on its axis and having an orbital motion around the nucleus. The Bohr magneton is a unit of magnetic moment, and it is defined as the magnetic moment of an electron in the ground state of a hydrogen atom.

Question 19

The diagram shows two small diamagnetic spheres, one near each end of a bar magnet.Which of the following statements is true?

Accepted Answer

The answer of The diagram shows two small diamagnetic spheres,...

Question 20

The intrinsic magnetic dipole moments of protons and neutrons are much less than that of an electron because:

Accepted Answer

The intrinsic magnetic dipole moments of protons and neutrons are much less than that of an electron primarily because their masses are greater. The magnetic moment is related to the charge-to-mass ratio, and since protons and neutrons are much more massive than electrons, their magnetic moments are correspondingly smaller.

Quiz 32: Maxwells Equations; Magnetism of Matter