Question 1

The magnetic field in a large rotating body can reverse direction periodically.For which two bodies in the solar system has evidence been found for such magnetic reversals?

Accepted Answer

Evidence has been found for magnetic reversals in both the Sun (observed through changes in its coronal emission) and Earth (known as geomagnetic reversals, which can be seen in the alignment of magnetic particles in rocks). There is no evidence for magnetic reversals in the Moon or Venus.

Question 2

Which statement about sunspots is NOT true?

Accepted Answer

Sunspots occur in regions of higher-than-average magnetic fields, not lower.

Question 3

Intense magnetic fields have been found to exist in sunspots by the observation of what specific physical effect?

Accepted Answer

The Zeeman effect is the splitting of spectral absorption lines when a magnetic field is present. This effect has been observed in sunspots, indicating the presence of strong magnetic fields in those regions.

Question 4

What change in spectral lines emitted by atoms is described by the Zeeman effect?

Accepted Answer

The Zeeman effect describes the splitting of spectral lines emitted by atoms when they are placed within an intense magnetic field. This effect was discovered by Pieter Zeeman in 1896 and is a result of the interaction between the magnetic field and the magnetic moment of the electrons in the atom. The splitting of the spectral lines allows for a more detailed study of the atom's properties and has important applications in fields such as astrophysics and quantum mechanics.

Question 5

What is a plasma?

Accepted Answer

A plasma is a gaslike mixture of ions and electrons. It is a distinct state of matter that exists at high temperatures or under high pressure, in which some or all of the atoms have lost or gained one or more electrons, creating both positive and negative particles. This makes it different from a regular gas, which is made up of neutral atoms. Plasmas are found in many places in the universe, including stars, lightning, and some types of flames.

Question 6

The strength of the magnetic field in a sunspot is estimated from Earth by:

Accepted Answer

The Zeeman effect is the splitting of atomic spectral lines when exposed to a magnetic field. By observing the wavelength splitting of these lines, the strength of the magnetic field can be estimated. Therefore, option D is the best choice for estimating the strength of the magnetic field in a sunspot from Earth.

Question 7

The differential rotation of the Sun causes the magnetic fields in its interior to become tangled.According to the Babcock model of the solar activity cycle,what happens to these tangled magnetic fields?

Accepted Answer

The Babcock model suggests that tangled magnetic fields interrupt convection currents, trapping gas that rises and carries the fields to the photosphere, forming sunspot groups.

Question 8

Which body does NOT exhibit some differential rotation?

Accepted Answer

The Moon does not exhibit differential rotation because it rotates at a constant rate, with its rotation period being equal to its orbital period around the Earth.

Question 9

The Zeeman effect refers to the:

Accepted Answer

The Zeeman effect refers to the splitting of spectral lines when a magnetic field is applied to atoms. This effect was first observed by Pieter Zeeman in 1896 and is caused by the interaction between the magnetic field and the magnetic moments of the atoms in the sample. The splitting of spectral lines can be used to measure the strength of magnetic fields in a variety of settings, including stars, planets, and laboratory experiments.

Question 10

Why are sunspots cooler than the rest of the Sun's surface?

Accepted Answer

Sunspots are cooler than the surrounding areas because they occur at points where the Sun's magnetic field is particularly strong, inhibiting the convective transport of heat from the Sun's interior to its surface.

Question 11

What is a plasma?

Accepted Answer

A plasma is a state of matter that is made up of electrons and ionized atoms. It is often referred to as the fourth state of matter, after solid, liquid, and gas. In a plasma, the electrons are separated from the nuclei, creating a highly ionized gas that can conduct electricity and respond strongly to electromagnetic fields. Examples of naturally occurring plasmas include lightning, the Sun's corona, and the aurora borealis. Plasmas are also used in many industrial and scientific applications, such as plasma cutting and welding, plasma TVs, and plasma thrusters for spacecraft.

Question 12

How can the rotation of the Sun be described?

Accepted Answer

The Sun exhibits differential rotation, where the equator rotates faster than the poles. However, this differential rotation does not extend all the way through the core; the core rotates more like a rigid body.

Question 13

In 1908,Hale noticed that the spectral lines from sunspots were split into closely spaced components,and he concluded that the magnetic fields in the sunspots must be very strong.What is the name given to this effect?

Accepted Answer

The Zeeman effect is the splitting of spectral lines in the presence of a magnetic field. It was first observed by Pieter Zeeman in 1896 and later studied by George Ellery Hale in the context of sunspots. Therefore, the correct option is choice D. The photoelectric effect, Doppler effect, and Hale effect are all different phenomena unrelated to the splitting of spectral lines due to magnetic fields.

Question 14

Sunspots are regions where the Sun's magnetic field penetrates the photosphere.What holds each spot together?

Accepted Answer

The answer of Sunspots are regions where the Sun's magnetic...

Question 15

The major feature that distinguishes a sunspot from other regions on the Sun is:

Accepted Answer

Sunspots are characterized by their strong and concentrated magnetic fields that suppress convection, leading to a reduction in surface temperature and a decrease in brightness compared to surrounding areas on the Sun.

Question 16

If the magnetic polarity of the north pole of the Sun at a particular time is N,what will be the polarity of the preceding or leading spot of a bipolar sunspot region rotating about the Sun in the northern hemisphere?

Accepted Answer

The answer of If the magnetic polarity of the north...

Question 17

How would one describe the Sun's rotation?

Accepted Answer

The outer layers of the Sun experience differential rotation, meaning that different parts of the Sun rotate at different rates. However, the inner regions of the Sun, including the core, rotate as a solid body. This is due to the fact that the Sun is mostly made up of plasma, which is a fluid state of matter that does not have a specific shape or form. As a result, the outer layers of the Sun can rotate independently of the inner regions.

Question 18

An astronomer observing certain regions of the Sun through a spectrometer notices that the spectral lines emitted from these regions are split into two or more components.What does the astronomer conclude about these regions from his observations?

Accepted Answer

Spectral lines splitting into multiple components is a characteristic of the Zeeman effect, which occurs when spectral lines are affected by strong magnetic fields. Therefore, the astronomer can conclude that the observed regions of the Sun contain strong magnetic fields.

Question 19

The Zeeman effect describes the change in wavelength of emitted light caused by:

Accepted Answer

The Zeeman effect is caused by magnetic fields acting on the radiating atoms, causing a splitting of spectral lines into multiple components with different polarizations and shifted wavelengths.

Question 20

What is a typical magnetic field strength inside a sunspot?

Accepted Answer

A typical magnetic field strength inside a sunspot is a few thousand times stronger than Earth's magnetic field. This is due to the intense convective activity inside the sunspot, which amplifies the magnetic field lines.

Quiz 9: The Sun: Our Extraordinary Ordinary Star

The magnetic field in a large rotating body can reverse direction periodically.For which two bodies in the solar system has evidence been found for such magnetic reversals?

Which statement about sunspots is NOT true?

Intense magnetic fields have been found to exist in sunspots by the observation of what specific physical effect?

What change in spectral lines emitted by atoms is described by the Zeeman effect?

What is a plasma?

The strength of the magnetic field in a sunspot is estimated from Earth by:

The differential rotation of the Sun causes the magnetic fields in its interior to become tangled.According to the Babcock model of the solar activity cycle,what happens to these tangled magnetic fields?

Which body does NOT exhibit some differential rotation?

The Zeeman effect refers to the:

Why are sunspots cooler than the rest of the Sun's surface?

What is a plasma?

How can the rotation of the Sun be described?

In 1908,Hale noticed that the spectral lines from sunspots were split into closely spaced components,and he concluded that the magnetic fields in the sunspots must be very strong.What is the name given to this effect?

Sunspots are regions where the Sun's magnetic field penetrates the photosphere.What holds each spot together?

The major feature that distinguishes a sunspot from other regions on the Sun is:

If the magnetic polarity of the north pole of the Sun at a particular time is N,what will be the polarity of the preceding or leading spot of a bipolar sunspot region rotating about the Sun in the northern hemisphere?

How would one describe the Sun's rotation?

An astronomer observing certain regions of the Sun through a spectrometer notices that the spectral lines emitted from these regions are split into two or more components.What does the astronomer conclude about these regions from his observations?

The Zeeman effect describes the change in wavelength of emitted light caused by:

What is a typical magnetic field strength inside a sunspot?