AST101 Class 12 Past Paper 2024 PDF

generate 50 questions with their answers for the uploaded document that will be used to study for a test Here are 50 questions along with their answers based on the content of the provided document: 1. What is the primary focus of AST101? The primary focus is on the Sun and its Neighbours,...

generate 50 questions with their answers for the uploaded document that will be used to study for a test Here are 50 questions along with their answers based on the content of the provided document: 1. What is the primary focus of AST101? The primary focus is on the Sun and its Neighbours, specifically the birth and properties of stars []. 2. What are the learning goals of Class 12? The learning goals are to understand the role of rotation in star birth and how nuclear fusion begins in a newborn star []. 3. How does squeezing gas affect temperature? Squeezing gas makes it hot. As the cloud collapses and gets denser, it heats up []. 4. What happens during the collapse of a gas cloud? The cloud heats up, and collisions between molecules create photons which can escape, slowing the increase in temperature and pressure []. 5. Where does a star begin to form in a collapsing cloud? A star begins to form in the center of the cloud, where temperatures and densities are highest []. 6. What occurs when the inner parts of a cloud become too dense? When the inner parts become too dense, photons can no longer es- cape, leading to a rise in temperature and a slowdown of collapse []. 7. What is a “naked” protostar? A “naked” protostar is formed when the winds and jets blow off the surrounding gas, leaving the protostar exposed []. 8. How do young hot stars affect their surroundings? Young hot stars heat up the clouds around them, push away layers, and have strong jets []. 9. What characterizes emission nebulae? Emission nebulae are regions lit up by young hot stars, composed of hydrogen gas, molecular clouds, and dust []. 10. What do protoplanetary discs form from? Protoplanetary discs form from the material surrounding a young star []. 11. How do planets form in a protoplanetary disc? Planets “scoop” up material in the protoplanetary disc as they form []. 12. What is the typical core temperature of a protostar? The typical core temperature of a protostar is around 1 million de- grees Celsius []. 13. What temperature is required for nuclear fusion to begin? Nuclear fusion begins when the core temperature hits 10 million de- grees Celsius []. 1 14. What does hydrostatic equilibrium refer to in stars? Hydrostatic equilibrium is the balance between the outward pressure of hot gas and the inward pull of gravity []. 15. What was the spin rate of the Sun 4.6 billion years ago? The spin rate of the Sun was once a week, compared to once a month now []. 16. What percentage of stars exist in pairs? More than 85% of stars exist in pairs []. 17. What are the four main components of a galaxy? 1. Molecular clouds (black) 2. Emission nebulae (pink) 3. Young stars (blue) 4. Old stars (yellow) []. 18. What is the significance of the color pink in nebulae? The pink color characterizes hot hydrogen gas at around 10,000 de- grees Celsius []. 19. What role does rotation play in star birth? Rotation leads to the formation of an accretion disk and protostellar jets []. 20. How does a gas cloud condense? A gas cloud condenses, heats up while compressing until hot enough for fusion to begin []. 21. What happens to the temperature and pressure as a collapsing cloud becomes denser? The temperature and pressure increase as the cloud collapses and becomes denser []. 22. What is created when the winds and jets blow off the surround- ing gas? A “naked” protostar is created []. 23. What is the composition of the Sun’s core now? The core is composed of 39% hydrogen and 60% helium []. 24. What is the effect of strong solar winds in young stars? Strong solar winds can significantly affect the surrounding environ- ment, pushing away material []. 25. What happens to the density of the outer parts of a collapsing cloud? The outer parts remain cool and low in density even as the inner parts collapse []. 26. What causes the balance in hydrostatic equilibrium? The balance is caused by the interplay of pressure from hot gas and gravitational pull []. 27. What are protostar jets? Protostar jets are streams of gas expelled from newly forming stars []. 28. How does a protostar become a star? A protostar becomes a star when nuclear fusion begins as the core temperature reaches the required level []. 29. What is the significance of accretion disks in star formation? 2  Accretion disks are essential for gathering material that leads to star formation []. 30. What temperature does hot hydrogen gas reach in emission neb- ulae? Hot hydrogen gas reaches around 10,000 degrees Celsius []. 31. How do we observe protoplanetary discs? Protoplanetary discs are observed using various astronomical instru- ments, such as ALMA and JWST []. 32. What is the role of jets in star formation? Jets help to remove excess material and energy from the forming star, promoting stable growth []. 33. What is the primary gas found in molecular clouds? The primary gas found in molecular clouds is hydrogen []. 34. How does the temperature of a protostar change over time? As the protostar forms, its core temperature rises until it is high enough to initiate nuclear fusion []. 35. What are solar flares, and how have they changed over time? Solar flares are bursts of radiation from the Sun; they were more frequent in the Sun’s early history []. 36. What is the difference between a star and a planet? A star undergoes nuclear fusion and emits its own light, while a planet does not and is typically smaller []. 37. What happens to the gas around a young star as it becomes hotter? The gas around the young star is heated, causing it to emit light and potentially form emission nebulae []. 38. What is the relationship between temperature and nuclear fu- sion? Higher temperatures are necessary to overcome gravitational forces for nuclear fusion to occur []. 39. What types of materials are found in planetary discs? Planetary discs consist of gas, dust, and other materials that can coalesce to form planets []. 40. What is the role of molecular clouds in star formation? Molecular clouds serve as the initial material from which stars form []. 41. What conditions lead to the formation of a protostar? Conditions of high density and temperature within a collapsing gas cloud lead to the formation of a protostar []. 42. What is the characteristic color of emission nebulae, and why? The characteristic color is pink due to the glowing hot hydrogen gas []. 43. How does the spin rate of the Sun compare now to its past? The Sun’s spin rate has decreased from once a week to once a month []. 44. What is the primary factor that influences how a star evolves? 3  The presence of nearby stars and their interactions can significantly influence a star’s evolution []. 45. What occurs in the core of a protostar as it becomes a star? The core temperature increases, leading to the initiation of nuclear fusion []. 46. What are the main components of a galaxy’s structure? Molecular clouds, emission nebulae, young stars, and old stars are the main components []. 47. How does the surrounding material affect a protostar? The surrounding material can provide additional mass for the proto- star and influence its development []. 48. What are the primary gases involved in star formation? Hydrogen and helium are the primary gases involved in the formation of stars []. 49. How does the anatomy of a young star differ from that of an older star? Young stars are hotter, brighter, and often have more solar activity compared to older stars []. 50. What astronomical instruments are used to study protoplane- tary discs? Instruments like the ALMA (Atacama Large Millimeter/submillimeter Array) and JWST (James Webb Space Telescope) are used []. These questions and answers cover a wide range of topics from the document, providing a comprehensive review for studying. 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