Question 1

Which of the following changes would cause the fusion rate in the Sun's core to increase?

Accepted Answer

An increase in the core temperature and A decrease in the core radius.

Question 2

Which of the following must occur for a star's core to reach equilibrium after an initial change in fusion rate?

Accepted Answer

If the fusion rate initially increases, then the core expands.If the fusion rate initially decreases, then the core contracts.

Question 3

What would happen if the fusion rate in the core of the Sun were increased but the core could not expand?

Accepted Answer

The Sun's core would start to heat up and the rate of fusion would increase even more

Question 4

What two physical processes balance each other to create the condition known as gravitational equilibrium in stars?

Accepted Answer

gravitational force and outward pressure

Question 5

The source of energy that keeps the Sun shining today is _________.

Accepted Answer

nuclear fusion

Question 6

To understand the interplay of observations and models you must first be able to distinguish between things that we observe and things that we infer from models. Consider the following statements about the Sun. Classify each statement as an observation or as an inference based on the current, accepted model for the Sun.

Accepted Answer

observation: The photosphere is made mostly of hydrogen and helium,The photosphere emits mostly visible light,The corona is hotter than the photosphere, The Sun emits neurtrinos and inferences: The Sun generates energy by fusing hydrogen into helium,The core temperature is 10 million k, The convection zone is cooler than the radiation zone,The composition of the photosphere is the same as that the gas cloud that have birth to our solar system.

Question 7

One statement about the Sun from Part A is The corona is hotter than the photosphere. Which of the following statements provides observational evidence for this claim?

Accepted Answer

We can calculate it by applying Newton's version of Kepler's third law with Earth's orbital period (1 year) and Earth's average distance from the Sun (1 AU).

Question 8

A solar model is used to calculate the expected temperature and density at all depths within the Sun. These results are then used to calculate the expected fusion rate within the Sun. We have confidence that the model is correct because it agrees with the observed characteristics of the Sun. Which of the following observations can be used to check that we really do know the Sun's internal fusion rate?

Accepted Answer

Measurements of the Sun's total energy output into space and Observations of neutrinos coming from the Sun.

Question 9

One statement about the Sun from Part A is The corona is hotter than the photosphere. Which of the following statements provides observational evidence for this claim?

Accepted Answer

The corona primarily emits X rays while the photosphere primarily emits visible light.

Question 10

Listed following are the different layers of the Sun. Rank these layers based on their distance from the Sun's center, from greatest to least.

Accepted Answer

Greatest distance corona, chromosphere, photosphere, convection zone, radiation zone, core. least distance.

Question 11

Rank the layers of the Sun based on their density, from highest to lowest.

Accepted Answer

core, radiation zone, convection zone,photosphere, chromosphere, corona.

Question 12

Rank the following layers of the Sun based on their temperature, from highest to lowest.

Accepted Answer

core, radiation zone, convective zone, photosphere.

Question 13

Rank the following layers of the Sun based on the pressure within them, from highest to lowest.

Accepted Answer

core, radiation zone, convective zone, photosphere.

Question 14

In which of the following layer(s) of the Sun does nuclear fusion occur?

Accepted Answer

core

Question 15

Which of the following layers of the Sun can be seen with some type of telescope? Consider all forms of light, but do not consider neutrinos or other particles

Accepted Answer

core, chromosphere, and photosphere.

Question 16

Solar energy leaves the core of the Sun in the form of

Accepted Answer

photons

Question 17

If fusion reactions were to suddenly shut off in the Sun, how would we be able to tell?

Accepted Answer

The Sun would begin to cool and get smaller and smaller as it morphs into a brown dwarf. The Earth would likewise slowly cool. It might be livable for a few more years besides for poor crop yields, famine, and expanding ice sheets. Given enough supplies, equipment, and fuel to heat themselves a small group of people might be able to survive on Earth for quite along time. The Earth's core would still be warm so I doubt Earth's atmosphere would freeze too quickly.The sun would begin to collapse,the collapse would maintain it's temperature and brightness at first.It would visibly shrink and slowly darken and very soon disappear from the naked eye

Astronomy

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