[
  {
    "order_number": "1",
    "question": "What is a galaxy?",
    "type": "mcq",
    "option_a": "A collection of planets",
    "option_b": "A collection of stars",
    "option_c": "A collection of asteroids",
    "option_d": "A collection of comets",
    "answer": "B",
    "explanation": "A galaxy is a collection of a very large number of stars mutually attracting one another through the gravitational force and staying together."
  },
  {
    "order_number": "2",
    "question": "Which of the following is the correct description of a star?",
    "type": "mcq",
    "option_a": "A celestial object that emits light through nuclear fusion reactions in its core",
    "option_b": "A planet-like object that orbits around a star",
    "option_c": "A type of planet that emits its own light",
    "option_d": "A cloud of interstellar gas and dust",
    "answer": "A celestial object that emits light through nuclear fusion reactions in its core",
    "explanation": "A star is a massive, luminous ball of gas, primarily hydrogen and helium, that emits energy through nuclear fusion reactions in its core."
  },
  {
    "order_number": "3",
    "question": "What is a main-sequence star?",
    "type": "mcq",
    "option_a": "A star that has run out of fuel",
    "option_b": "A star that is undergoing nuclear fusion of hydrogen into helium",
    "option_c": "A star that is about to explode",
    "option_d": "A star that is very small and has low temperature",
    "answer": "B",
    "explanation": "A main-sequence star is a normal star that is undergoing nuclear fusion of hydrogen into helium."
  },
  {
    "order_number": "4",
    "question": "What is a white dwarf?",
    "type": "mcq",
    "option_a": "A type of galaxy",
    "option_b": "A type of star that is undergoing nuclear fusion of hydrogen into helium",
    "option_c": "The remnant of a red giant star",
    "option_d": "The remnant of a white dwarf after it has cooled down, resulting in very low luminosity",
    "answer": "The remnant of a white dwarf after it has cooled down, resulting in very low luminosity",
    "explanation": "A white dwarf is the final stage of evolution of a star similar to our Sun. After it has expended all its nuclear fuel, it will slowly cool down to become a black dwarf."
  },
  {
    "order_number": "5",
    "question": "What is a brown dwarf?",
    "type": "mcq",
    "option_a": "A star that has run out of fuel",
    "option_b": "A star that is undergoing nuclear fusion of hydrogen into helium",
    "option_c": "Gas and dust that did not reach a high enough temperature to initiate fusion",
    "option_d": "A very small star with low temperature",
    "answer": "C",
    "explanation": "A brown dwarf is gas and dust that did not reach a high enough temperature to initiate fusion. These objects continue to compact and cool down."
  },
  {
    "order_number": "6",
    "question": "What is a cluster of galaxies?",
    "type": "mcq",
    "option_a": "A group of planets that are close to each other",
    "option_b": "A group of stars that are close to each other",
    "option_c": "Galaxies in close proximity to one another and affecting each other gravitationally, behaving as one unit",
    "option_d": "A group of asteroids that have collided with each other",
    "answer": "Galaxies in close proximity to one another and affecting each other gravitationally, behaving as one unit",
    "explanation": "A cluster of galaxies is a group of galaxies that are bound together by gravity and move together through space."
  },
  {
    "order_number": "7",
    "question": "What is a supernova?",
    "type": "mcq",
    "option_a": "The explosion of a white dwarf that has accreted mass from a companion star exceeding its stability limit",
    "option_b": "The explosion of a red supergiant star",
    "option_c": "The end result of the explosion of a red giant",
    "option_d": "A star that has run out of fuel",
    "answer": "B",
    "explanation": "A supernova is the explosion of a red supergiant star. The amount of energy emitted in a supernova explosion can be staggering - comparable to the total energy radiated by our Sun in its entire lifetime!"
  },
  {
    "order_number": "8",
    "question": "What is dark matter?",
    "type": "mcq",
    "option_a": "Matter that is too cold to radiate",
    "option_b": "A type of matter that emits light in the absence of a light source",
    "option_c": "The matter that makes up stars and galaxies",
    "option_d": "The mass of a black hole",
    "answer": "Matter that is too cold to radiate",
    "explanation": "Dark matter is a form of matter that can not be seen or detected through electromagnetic radiation, but whose existence is inferred from its gravitational effects on visible matter."
  },
  {
    "order_number": "9",
    "question": "What is a white dwarf?",
    "type": "mcq",
    "option_a": "The end result of the explosion of a red giant",
    "option_b": "A star that is undergoing nuclear fusion of hydrogen into helium",
    "option_c": "The end result of the explosion of a white dwarf",
    "option_d": "A very small star with low temperature",
    "answer": "C",
    "explanation": "A white dwarf is the end result of the explosion of a red giant. A small, dense star (about the size of the Earth), in which no nuclear reactions take place. It is very hot but its small size gives it a very low luminosity."
  },
  {
    "order_number": "10",
    "question": "What is the main source of energy in a star?",
    "type": "mcq",
    "option_a": "Nuclear fusion of hydrogen into helium",
    "option_b": "Nuclear fission of uranium",
    "option_c": "Chemical reactions",
    "option_d": "Solar wind",
    "answer": "Nuclear fusion of hydrogen into helium",
    "explanation": "Nuclear fusion provides the energy needed to keep the star hot, oppose gravitational contraction, and provide energy that is radiated into space."
  },
  {
    "order_number": "11",
    "question": "What is a red giant?",
    "type": "mcq",
    "option_a": "A star that is undergoing nuclear fusion of hydrogen into helium",
    "option_b": "A star that has run out of fuel",
    "option_c": "A very small star with low temperature",
    "option_d": "A main-sequence star",
    "answer": "A",
    "explanation": "A red giant is a main-sequence star that evolves into a red giant - a very large, reddish star. There are nuclear reactions involving the fusion of helium into heavier elements."
  },
  {
    "order_number": "12",
    "question": "What is luminosity?",
    "type": "mcq",
    "option_a": "The unit of apparent brightness",
    "option_b": "The distance to a star",
    "option_c": "The size of a star",
    "option_d": "The power radiated by a star",
    "answer": "The power radiated by a star",
    "explanation": "The power radiated by a star is known in astrophysics as the luminosity. It is measured in watts."
  },
  {
    "order_number": "13",
    "question": "What is a neutron star?",
    "type": "mcq",
    "option_a": "The end result of the explosion of a red giant",
    "option_b": "A star consisting almost entirely of neutrons",
    "option_c": "A very small star with low temperature",
    "option_d": "A star that is undergoing nuclear fusion of hydrogen into helium",
    "answer": "B",
    "explanation": "A neutron star is the end result of the explosion of a red supergiant; a very small star (a few tens of kilometres in diameter) and very dense. This is a star consisting almost entirely of neutrons. The neutrons form a superfluid around a core of immense pressure and density. A neutron star is an astonishing macroscopic example of microscopic quantum physics."
  },
  {
    "order_number": "14",
    "question": "What is a comet?",
    "type": "mcq",
    "option_a": "A small planet-like object that orbits around a star",
    "option_b": "A cloud of interstellar gas and dust",
    "option_c": "A massive ball of gas and dust held together by its own gravity",
    "option_d": "A small body mainly composed of ice and dust that orbits around a star",
    "answer": "A small body mainly composed of ice and dust that orbits around a star",
    "explanation": "Comets are small bodies mainly composed of ice and dust that orbit around the Sun in an elliptical orbit."
  },
  {
    "order_number": "15",
    "question": "What is a black hole?",
    "type": "mcq",
    "option_a": "A singularity in space time; the end result of the evolution of a very massive star",
    "option_b": "A very small star with low temperature",
    "option_c": "A star that is undergoing nuclear fusion of hydrogen into helium",
    "option_d": "A star that has run out of fuel",
    "answer": "A",
    "explanation": "A black hole is a singularity in space time; the end result of the evolution of a very massive star."
  },
  {
    "order_number": "16",
    "question": "What is a neutron star?",
    "type": "mcq",
    "option_a": "The end result of the explosion of a red supergiant star",
    "option_b": "A type of cluster of galaxies",
    "option_c": "A star that is undergoing nuclear fusion of hydrogen into helium",
    "option_d": "A very small star (a few tens of kilometers in diameter) and very dense, consisting almost entirely of neutrons",
    "answer": "A very small star (a few tens of kilometers in diameter) and very dense, consisting almost entirely of neutrons",
    "explanation": "A neutron star is the end result of the explosion of a red supergiant star. It is an incredibly dense ball of neutrons that can be only a few kilometers in diameter."
  },
  {
    "order_number": "17",
    "question": "What is a planetary nebula?",
    "type": "mcq",
    "option_a": "Clouds of dust in the space between stars",
    "option_b": "The ejected envelope of a red giant star",
    "option_c": "A group of stars that are physically near each other in space",
    "option_d": "Galaxies close to one another and affecting one another gravitationally, behaving as one unit",
    "answer": "B",
    "explanation": "A planetary nebula is the ejected envelope of a red giant star."
  },
  {
    "order_number": "18",
    "question": "What is a brown dwarf?",
    "type": "mcq",
    "option_a": "A very small star with low temperature, reddish in color",
    "option_b": "Gas and dust that did not reach a high enough temperature to initiate fusion",
    "option_c": "The ejected envelope of a red giant star",
    "option_d": "A star of variable luminosity",
    "answer": "Gas and dust that did not reach a high enough temperature to initiate fusion",
    "explanation": "Brown dwarfs are objects that are not massive enough to sustain nuclear fusion reactions in their cores. As a result, they slowly cool down over time."
  },
  {
    "order_number": "19",
    "question": "What is dark matter?",
    "type": "mcq",
    "option_a": "Matter in galaxies and clusters of galaxies that is too cold to radiate",
    "option_b": "Gases and dust filling the space between stars",
    "option_c": "A star that is undergoing nuclear fusion of hydrogen into helium",
    "option_d": "A singularity in space time",
    "answer": "A",
    "explanation": "Dark matter is generic name for matter in galaxies and clusters of galaxies that is too cold to radiate. Its existence is inferred from techniques other than direct visual observation."
  },
  {
    "order_number": "20",
    "question": "What is a cepheid variable?",
    "type": "mcq",
    "option_a": "A type of nebula",
    "option_b": "A type of comet",
    "option_c": "A star with variable luminosity that varies in brightness in a well-defined pattern",
    "option_d": "A type of cluster of galaxies",
    "answer": "A star with variable luminosity that varies in brightness in a well-defined pattern",
    "explanation": "Cepheid variables are stars that pulsate in a regular pattern, with a well-defined period. This period is related to the absolute luminosity of the star, which can be used to estimate the distance to the star via parallax."
  },
  {
    "order_number": "21",
    "question": "What is the interstellar medium?",
    "type": "mcq",
    "option_a": "The matter that makes up stars and galaxies",
    "option_b": "A cloud of interstellar gas and dust",
    "option_c": "The dark matter holding galaxies and clusters of galaxies together",
    "option_d": "A group of planets that are close to each other",
    "answer": "A cloud of interstellar gas and dust",
    "explanation": "The interstellar medium is the gas and dust that fills the space between stars in a galaxy. It is mainly composed of hydrogen and helium, along with small amounts of heavier elements and dust grains."
  },
  {
    "order_number": "22",
    "question": "What is a planetary nebula?",
    "type": "mcq",
    "option_a": "The end result of the explosion of a red giant star",
    "option_b": "A cloud of interstellar gas and dust",
    "option_c": "The ejected envelope of a red giant star",
    "option_d": "A small body mainly composed of ice and dust that orbits around a star",
    "answer": "The ejected envelope of a red giant star",
    "explanation": "When a low-to-intermediate mass star expands into a red giant, it loses its outer layers into space, producing a planetary nebula. The core of the star that is left behind becomes a white dwarf."
  },
  {
    "order_number": "23",
    "question": "What is a main-sequence star?",
    "type": "mcq",
    "option_a": "The ejected envelope of a red giant star",
    "option_b": "A type of star that is undergoing nuclear fusion of hydrogen into helium",
    "option_c": "A very small star (a few tens of kilometers in diameter) and very dense, consisting almost entirely of neutrons",
    "option_d": "A small body mainly composed of ice and dust that orbits around a star",
    "answer": "A type of star that is undergoing nuclear fusion of hydrogen into helium",
    "explanation": "A main-sequence star is a normal star that is undergoing nuclear fusion of hydrogen into helium in its core. This is the phase in which our Sun is currently in."
  },
  {
    "order_number": "24",
    "question": "What is a red giant?",
    "type": "mcq",
    "option_a": "Gas and dust that did not reach a high enough temperature to initiate fusion",
    "option_b": "The end result of the explosion of a white dwarf",
    "option_c": "A small body mainly composed of ice and dust that orbits around a star",
    "option_d": "A normal star that has evolved into a very large, reddish star",
    "answer": "A normal star that has evolved into a very large, reddish star",
    "explanation": "A red giant is a normal star that has evolved past the main-sequence phase and has become a large, reddish star due to nuclear reactions that cause it to expand."
  },
  {
    "order_number": "25",
    "question": "What is a black hole?",
    "type": "mcq",
    "option_a": "A type of planet that emits its own light",
    "option_b": "A singularity in space-time; the end result of the evolution of a very massive star",
    "option_c": "The mass of a neutron star",
    "option_d": "A massive ball of gas and dust held together by its own gravity",
    "answer": "A singularity in space-time; the end result of the evolution of a very massive star",
    "explanation": "A black hole is a region of space-time where gravity is so strong that nothing, not even light, can escape from it. It is the end result of the evolution of a very massive star."
  },
  {
    "order_number": "26",
    "question": "Which statement best describes a black dwarf?",
    "type": "mcq",
    "option_a": "The ejected envelope of a red giant star",
    "option_b": "A small body mainly composed of ice and dust that orbits around a star",
    "option_c": "A type of star that is undergoing nuclear fusion of hydrogen into helium",
    "option_d": "The remnant of a white dwarf after it has cooled down, resulting in very low luminosity",
    "answer": "The remnant of a white dwarf after it has cooled down, resulting in very low luminosity",
    "explanation": "A black dwarf is the remnant of a white dwarf after it has cooled down to the point where it no longer emits any visible light."
  },
  {
    "order_number": "27",
    "question": "What is an astronomical unit (AU)?",
    "type": "mcq",
    "option_a": "The average distance between the Earth and the Sun.",
    "option_b": "The radius of the Earth.",
    "option_c": "The distance traveled by light in one year.",
    "option_d": "The mass of the Earth.",
    "answer": "The average distance between the Earth and the Sun.",
    "explanation": "An astronomical unit or AU is a unit of measurement equal to the average distance between Earth and the Sun. It is commonly used to measure distances within our solar system."
  },
  {
    "order_number": "28",
    "question": "Which of the following is not a type of galaxy?",
    "type": "mcq",
    "option_a": "Elliptical",
    "option_b": "Spiral",
    "option_c": "Irregular",
    "option_d": "Spherical",
    "answer": "Spherical",
    "explanation": "The three main types of galaxies are elliptical, spiral, and irregular. There is no galaxy type called spherical."
  },
  {
    "order_number": "29",
    "question": "What is a cepheid variable?",
    "type": "mcq",
    "option_a": "A type of black hole",
    "option_b": "A star of variable luminosity",
    "option_c": "A type of planetary nebula",
    "option_d": "A cluster of galaxies",
    "answer": "A star of variable luminosity",
    "explanation": "A cepheid variable is a star that pulsates in a regular pattern, causing its luminosity to vary. The period of this pulsation is related to the star\u2019s absolute luminosity, allowing it to be used as a standard candle to measure distances in space."
  },
  {
    "order_number": "30",
    "question": "Which of the following objects is composed mainly of ice and dust?",
    "type": "mcq",
    "option_a": "A black hole",
    "option_b": "A brown dwarf",
    "option_c": "A comet",
    "option_d": "A neutron star",
    "answer": "A comet",
    "explanation": "Comets are small, icy objects that orbit the Sun. When a comet gets close enough to the Sun, its ice melts and forms a brightly glowing coma around it."
  },
  {
    "order_number": "31",
    "question": "What is the difference between apparent brightness and luminosity?",
    "type": "mcq",
    "option_a": "Apparent brightness is a measure of how much light is emitted by a star, while luminosity is a measure of how bright the star appears from Earth.",
    "option_b": "Apparent brightness is a measure of how bright a star appears from Earth, while luminosity is a measure of how much light is emitted by the star.",
    "option_c": "Apparent brightness is a measure of the distance between Earth and a star, while luminosity is a measure of the star\u2019s mass.",
    "option_d": "Apparent brightness is a measure of the star\u2019s mass, while luminosity is a measure of the distance between Earth and the star.",
    "answer": "Apparent brightness is a measure of how bright a star appears from Earth, while luminosity is a measure of how much light is emitted by the star.",
    "explanation": "Apparent brightness is a measure of how much light from a star reaches Earth, while luminosity is a measure of the total amount of energy emitted by a star in all directions. Luminosity is an intrinsic property of a star, while apparent brightness depends on the star\u2019s luminosity and its distance from Earth."
  },
  {
    "order_number": "32",
    "question": "What is a main-sequence star?",
    "type": "mcq",
    "option_a": "A star that is undergoing nuclear fusion of hydrogen into helium.",
    "option_b": "A star that has exhausted its fuel and is in the process of burning helium.",
    "option_c": "A star that has evolved off the main sequence and is fusing heavier elements.",
    "option_d": "A star that has exploded as a supernova.",
    "answer": "A star that is undergoing nuclear fusion of hydrogen into helium.",
    "explanation": "A main-sequence star is a normal star that is fusing hydrogen into helium in its core. This is the most common type of star, and includes the Sun."
  },
  {
    "order_number": "33",
    "question": "What is a brown dwarf?",
    "type": "mcq",
    "option_a": "A star that has exploded as a supernova.",
    "option_b": "A star that is undergoing nuclear fusion of hydrogen into helium.",
    "option_c": "Gas and dust that did not reach a high enough temperature to initiate fusion.",
    "option_d": "The ejected envelope of a red giant star.",
    "answer": "Gas and dust that did not reach a high enough temperature to initiate fusion.",
    "explanation": "A brown dwarf is an object that is too cool and small to undergo sustained nuclear fusion of hydrogen in its core, but is too hot and massive to be called a planet. They are often described as \u2018failed stars\u2019."
  },
  {
    "order_number": "34",
    "question": "What is a supernova?",
    "type": "mcq",
    "option_a": "The explosion of a red giant star.",
    "option_b": "The end result of the evolution of a very massive star.",
    "option_c": "A singularity in space-time.",
    "option_d": "The ejected envelope of a red giant star.",
    "answer": "The explosion of a star.",
    "explanation": "A supernova is a catastrophic explosion that occurs at the end of a star\u2019s life. The explosion can outshine an entire galaxy for a brief period of time."
  },
  {
    "order_number": "35",
    "question": "What is dark matter?",
    "type": "mcq",
    "option_a": "Matter in galaxies that is too cold to radiate and is inferred from techniques other than direct visual observation.",
    "option_b": "The ejected envelope of a red giant star.",
    "option_c": "Space-time that is so warped that nothing can escape it, not even light.",
    "option_d": "Matter that is made up of subatomic particles that do not interact with the electromagnetic force.",
    "answer": "Matter in galaxies that is too cold to radiate and is inferred from techniques other than direct visual observation.",
    "explanation": "Dark matter is matter that is inferred to exist from its gravitational effects but does not emit or absorb light, and therefore cannot be detected directly by telescopes."
  },
  {
    "order_number": "36",
    "question": "What is a black hole?",
    "type": "mcq",
    "option_a": "A type of galaxy in which most of the stars are very old and have mostly red colours.",
    "option_b": "A singularity in space-time that is the end result of the evolution of a very massive star.",
    "option_c": "A star that has exhausted its fuel and is in the process of burning helium.",
    "option_d": "A star that has exploded as a supernova.",
    "answer": "A singularity in space-time that is the end result of the evolution of a very massive star.",
    "explanation": "A black hole is a region of space-time where gravity is so strong that nothing, not even light, can escape its pull. They are formed from the collapse of very massive stars."
  },
  {
    "order_number": "37",
    "question": "Which of the following is not a type of nebula?",
    "type": "mcq",
    "option_a": "Planetary Nebula",
    "option_b": "Stellar Nebula",
    "option_c": "Reflection Nebula",
    "option_d": "Irregular Nebula",
    "answer": "Stellar Nebula",
    "explanation": "Stellar nebula is not a type of nebula. The three main types of nebula are emission nebula, reflection nebula, and planetary nebula."
  },
  {
    "order_number": "38",
    "question": "What is nuclear fusion?",
    "type": "mcq",
    "option_a": "The process by which a star burns helium into heavier elements in its core.",
    "option_b": "The process by which a star burns hydrogen into helium in its core.",
    "option_c": "The process by which a planet forms from a cloud of gas and dust.",
    "option_d": "The process by which a star expands into a red giant.",
    "answer": "The process by which a star burns hydrogen into helium in its core.",
    "explanation": "Nuclear fusion is the process by which a star generates energy by fusing hydrogen atoms into helium atoms in its core. This process releases a tremendous amount of energy in the form of light and heat."
  },
  {
    "order_number": "39",
    "question": "What is a red giant?",
    "type": "mcq",
    "option_a": "A star that has exploded as a supernova.",
    "option_b": "A star that is undergoing nuclear fusion of hydrogen into helium.",
    "option_c": "A star that has exhausted its fuel and is in the process of burning helium.",
    "option_d": "A star that has evolved off the main sequence and is fusing heavier elements.",
    "answer": "A star that has evolved off the main sequence and is fusing heavier elements.",
    "explanation": "A red giant is a star that has exhausted the supply of hydrogen in its core and is now fusing heavier elements. This causes the star to expand and become much larger and redder than before."
  },
  {
    "order_number": "40",
    "question": "What is a white dwarf?",
    "type": "mcq",
    "option_a": "The end result of the explosion of a red giant.",
    "option_b": "A small, dense star that is fusing helium into heavier elements in its core.",
    "option_c": "A small, dense star that is no longer generating energy through nuclear fusion.",
    "option_d": "A star that is undergoing nuclear fusion of hydrogen into helium.",
    "answer": "A small, dense star that is no longer generating energy through nuclear fusion.",
    "explanation": "A white dwarf is the end result of the evolution of a low- to medium-mass star. It is a small, dense star that is no longer generating energy through nuclear fusion. White dwarfs are very hot and faint, and will eventually cool down over billions of years."
  },
  {
    "order_number": "41",
    "question": "What is a black dwarf?",
    "type": "mcq",
    "option_a": "The end result of the explosion of a red giant.",
    "option_b": "A type of black hole with very low mass.",
    "option_c": "Gas and dust that did not reach a high enough temperature to initiate fusion.",
    "option_d": "The remnant of a white dwarf after it has cooled down.",
    "answer": "The remnant of a white dwarf after it has cooled down.",
    "explanation": "A black dwarf is a hypothetical object that would be the end result of the evolution of a white dwarf. It is essentially a cold, dark object made purely of carbon and oxygen atoms. However, the universe is not old enough for any white dwarfs to have cooled down enough to become black dwarfs yet."
  }
]