Role of Nuclear Fusion Stars

The Sun and other stars are powered by nuclear fusion. Which of these statements correctly describes one of the processes that occur during nuclear fusion in stars?

• Helium nuclei combine to become a hydrogen nucleus, releasing energy.

• Hydrogen nuclei combine to become a helium nucleus, absorbing energy.

• Hydrogen nuclei combine to become a helium nucleus, releasing energy.

• Four helium nuclei combine to become a hydrogen nucleus, absorbing energy.

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NGSS.HS-PS1-8

A student observes the Milky Way galaxy in the night sky. Which characteristic of the galaxy makes it visible?

• Billions of stars in the galaxy carry out nuclear fusion.

• Tons of compressed matter begin to radiate visible light from the galaxy center.

• The galaxy spins at a speed that generates a large amount of molecular friction.

• The galaxy’s stellar nebulae reflect the Sun’s light.

Which accurately describes the process stars use to convert matter into energy?

• Atoms split, decreasing the average size of atomic nuclei.

• Atoms release electrons to form positive ions.

• Atoms acquire electrons to form negative ions.

• Atoms fuse, increasing the average size of atomic nuclei

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NGSS.HS-PS1-8

Which of the following correctly describes how the Sun produces energy?

• One hydrogen atom and one lithium atom divide into one helium atom.

• One hydrogen atom and four helium atoms divide into one lithium atom.

• Hydrogen atoms combine into one helium atom.

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NGSS.HS-PS1-8

Which of these statements is MOST accurate about the Sun?

• It has an infinite energy supply

• It is near the end of its life cycl

• It is in its infancy in terms of energy consumption.

• It has consumed approximately one-half of its expendable energy.

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A student reads the following statement about star formation.

Matter in a stellar nebula begins to give off heat and light when it reaches a temperature of 15,000,000°C.

Why is this temperature necessary for a star to begin radiating energy?

• Carbon nuclei remain stable until high temperatures are reache

• Hydrogen atoms require high temperatures for the nuclei to fuse.

• High temperatures provide the energy needed for combustion to begin.

• High temperatures are needed to increase the kinetic energy of heavy atoms

In which layer of the Sun does nuclear fusion occur?

• core

• radiative zone

• convection zone

• chromosphere

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