1.
What is the outermost layer of the sun?
Correct Answer
C. pHotospHere
Explanation
The outermost layer of the sun is called the photosphere. This is the layer that emits the visible light that we see from Earth. It is also the layer where sunspots, solar flares, and other solar phenomena occur. The photosphere has a temperature of about 5,500 degrees Celsius and is composed mainly of hydrogen gas. It is the layer that we commonly refer to as the "surface" of the sun, even though it is not a solid surface like the Earth's.
2.
What layer of the Sun is the hottest?
Correct Answer
D. Core
Explanation
The core of the Sun is the hottest layer. It is the central region where nuclear fusion occurs, releasing enormous amounts of energy in the form of heat and light. The temperature in the core can reach up to 27 million degrees Fahrenheit (15 million degrees Celsius), making it the hottest part of the Sun.
3.
As you go deeper in the sun, what happens to the temperature?
Correct Answer
C. Temperature will increase
Explanation
As you go deeper into the sun, the temperature will increase. This is because the sun's core is where nuclear fusion occurs, which generates immense heat and energy. As you move closer to the core, the pressure and density of the sun's gases increase, causing the temperature to rise. Therefore, the deeper you go into the sun, the hotter it becomes.
4.
Which of the following does not occur in nuclear fusion?
Correct Answer
B. Mass is released
Explanation
In nuclear fusion, the process involves the combination of two atomic nuclei to form a larger nucleus. During this process, a small amount of mass is converted into energy according to Einstein's equation E=mc^2. Therefore, mass is not released in nuclear fusion, but rather converted into energy. This is in contrast to nuclear fission, where mass is indeed released as a result of splitting an atomic nucleus.
5.
Why does nuclear fusion only happen in the core?
Correct Answer
A. The core is very hot
Explanation
Nuclear fusion only happens in the core because it is very hot. Fusion occurs when atoms collide with enough energy to overcome the electrostatic repulsion between their positively charged nuclei. The high temperature in the core provides the necessary energy for these collisions to happen, allowing fusion reactions to take place.
6.
Why can larger stars fuse larger atoms together?
Correct Answer
C. They have a higher pressure so they have a higher temperature
Explanation
Larger stars have a higher pressure due to their immense gravitational pull. This increased pressure leads to a higher temperature within the star. The higher temperature allows for the fusion of larger atoms because it provides the necessary energy to overcome the electrostatic repulsion between the positively charged nuclei. Thus, the higher pressure in larger stars results in a higher temperature, enabling the fusion of larger atoms.
7.
What is the largest element the Sun will be able to make?
Correct Answer
C. Oxygen
Explanation
The Sun is a massive ball of gas, primarily composed of hydrogen and helium. Through the process of nuclear fusion, hydrogen atoms in the Sun's core combine to form helium. Eventually, when the Sun exhausts its hydrogen fuel, it will start fusing helium atoms to produce heavier elements like oxygen. Therefore, oxygen is the largest element the Sun will be able to make.
8.
The hottest stars in the sky are large. What color are most of these very hot stars?
Correct Answer
B. Blue
Explanation
The hottest stars in the sky are large and emit a high amount of energy. This energy is produced by nuclear fusion reactions in their cores, causing them to emit a bluish-white light. This is due to the high temperature of these stars, which causes them to emit shorter wavelength light, resulting in a blue color. Therefore, most of these very hot stars appear blue in color.
9.
Our Sun will eventually die off. What will it be at the point that it stops nuclear fusion?
Correct Answer
C. White dwarf
Explanation
When our Sun exhausts its nuclear fuel and stops nuclear fusion, it will transform into a white dwarf. A white dwarf is the final stage in the life cycle of a star like the Sun. It is a dense, hot, and compact stellar remnant that remains after the outer layers of the star are expelled into space. The core of the star collapses under its own gravity, while the outer layers form a planetary nebula. The white dwarf will gradually cool down over billions of years, eventually becoming a cold, dark object known as a black dwarf.
10.
Stars that are in the red giant region are considered ___________. (fill in the blank)
Correct Answer
C. Old
Explanation
Stars that are in the red giant region are considered old because the red giant phase is a later stage in the evolution of a star. During this phase, the star has exhausted its core hydrogen fuel and has expanded and cooled down. This typically happens to stars that are nearing the end of their life cycle. Therefore, stars in the red giant region are generally older stars.