Quiz and Flashcards on Energy Balance in the Sun

Questions and Answers

According to modern science, approximately how old is the Sun?

10,000 years

4 1/2 billion years (correct)

400 million years

25 million years

The Sun will exhaust its nuclear fuel in about ______.

5000 AD

50 billion years

5 million years

5 billion years (correct)

Which of the following correctly describes how the process of gravitational contraction can make a star hot?

Gravitational contraction involves the generation of heat by chemical reactions, much like the burning of coal.

When a star contracts in size, gravitational potential energy is converted to thermal energy. (correct)

Gravitational contraction involves nuclear fusion, which generates a lot of heat.

Heat is generated when gravity contracts, because gravity is an inverse square law force.

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

nuclear fusion Signup and view all the answers

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

gravitational force and outward pressure Signup and view all the answers

Energy balance in the Sun refers to a balance between _________.

the rate at which fusion generates energy in the Sun's core and the rate at which the Sun's surface radiates energy into space Signup and view all the answers

When we say that the Sun is a ball of plasma, we mean that _________.

the Sun consists of gas in which many or most of the atoms are ionized (missing electrons) Signup and view all the answers

What is the Sun made of (by mass)?

70% hydrogen, 28% helium, 2% other elements Signup and view all the answers

From center outward, which of the following lists the 'layers' of the Sun in the correct order?

Core, radiation zone, convection zone, photosphere, chromosphere, corona Signup and view all the answers

What are the appropriate units for the Sun's luminosity?

watts Signup and view all the answers

The Sun's surface, as we see it with our eyes, is called the _________.

photosphere Signup and view all the answers

The Sun's average surface (photosphere) temperature is about ______.

5,800 K Signup and view all the answers

What is the solar wind?

a stream of charged particles flowing outward from the surface of the Sun Signup and view all the answers

The fundamental nuclear reaction occurring in the core of the Sun is _________.

nuclear fusion of hydrogen into helium Signup and view all the answers

The proton-proton chain is _________.

the specific set of nuclear reactions through which the Sun fuses hydrogen into helium Signup and view all the answers

The overall result of the proton-proton chain is:

4 H becomes 1 He + energy Signup and view all the answers

To estimate the central temperature of the Sun, scientists _________.

use computer models to predict interior conditions Signup and view all the answers

Why are neutrinos so difficult to detect?

They have a tendency to pass through just about any material without any interactions. Signup and view all the answers

The light radiated from the Sun's surface reaches Earth in about 8 minutes, but the energy of that light was released by fusion in the solar core about _________.

a few hundred thousand years ago Signup and view all the answers

What happens to energy in the Sun's convection zone?

Energy is transported outward by the rising of hot plasma and sinking of cooler plasma. Signup and view all the answers

What do sunspots, solar prominences, and solar flares all have in common?

They are all strongly influenced by magnetic fields on the Sun. Signup and view all the answers

Which of the following is not a characteristic of the 11-year sunspot cycle?

The sunspot cycle is very steady, so that each 11-year cycle is nearly identical to every other 11-year cycle. Signup and view all the answers

How is the sunspot cycle directly relevant to us here on Earth?

Coronal mass ejections and other activity associated with the sunspot cycle can disrupt radio communications and knock out sensitive electronic equipment. Signup and view all the answers

Study Notes

Sun's Age and Future

The Sun is approximately 4.5 billion years old.
It is projected to exhaust its nuclear fuel in about 5 billion years.

Stellar Physics

Gravitational contraction heats a star by converting gravitational potential energy into thermal energy upon contraction.
The Sun generates energy through nuclear fusion, primarily converting hydrogen into helium.

Gravitational Equilibrium

Gravitational equilibrium is achieved through the balance of gravitational force and outward pressure.
Energy balance in the Sun refers to the equivalence of energy production in the core and energy radiation at the surface.

Composition and Structure

The Sun is composed of about 70% hydrogen, 28% helium, and 2% other elements.
The correct structural order of the Sun is: Core, radiation zone, convection zone, photosphere, chromosphere, corona.

Solar Characteristics

The luminosity of the Sun is measured in watts.
The visible surface of the Sun is called the photosphere, with an average temperature around 5,800 K.

Solar Wind and Nuclear Reactions

The solar wind consists of a stream of charged particles emitted from the Sun's surface.
The fundamental nuclear reaction in the Sun is the fusion of hydrogen into helium through the proton-proton chain.

Photon Behavior and Models

Energy in the Sun's convection zone is transferred by the rising of hot plasma and the sinking of cooler plasma.
Estimation of the central temperature of the Sun relies on computer models.

Neutrinos and Light Travel Time

Neutrinos are challenging to detect because they can pass through matter with minimal interactions.
The light observed from the Sun takes about 8 minutes to reach Earth, while the energy generating that light originated in the solar core several hundred thousand years prior.

Solar Activity

Sunspots, solar prominences, and solar flares are influenced by solar magnetic fields.
The 11-year sunspot cycle involves variations in sunspot numbers and associated solar phenomena, including increased activity (e.g., solar flares) when sunspots are more frequent.

Earth-Sun Relationships

Solar cycles can affect Earth's technology, as coronal mass ejections may disrupt communications and electronic devices.
The sunspot cycle can influence radio communications but is not directly linked to global warming or Earth weather patterns.

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Description

Test your knowledge on the Sun, its age, future, and physical characteristics. This quiz covers stellar physics concepts like gravitational equilibrium, nuclear fusion, and the Sun's composition. Explore the intricate structures of our star and learn about its life cycle.

Stellar Physics: The Sun's Age and Structure