Question 1: Define a nebula and explain its role in the formation of stars.

Answer: A nebula is a cloud of gas and dust in space that serves as the birth site for new stars by collapsing under gravity to form a protostar.

Question 2: Describe the main process that causes a star to evolve from a main sequence star to a red giant.

Answer: A star expands into a red giant when it exhausts hydrogen in its core, causing the core to contract and the outer layers to expand due to increased fusion in a surrounding shell.

Question 3: Explain the difference between a white dwarf and a neutron star.

Answer: A white dwarf is a dense, dim remnant of a low to medium mass star, primarily composed of electron-degenerate matter, while a neutron star is a collapsed core of a massive star, mainly made of neutrons, and is much denser.

Question 4: What determines whether a star ends its life as a neutron star or a black hole?

Answer: The initial mass of the star; stars with masses greater than about 20-25 times the Sun's mass tend to become black holes, while less massive stars may become neutron stars.

Question 5: Calculate the gravitational potential energy of a black hole with a mass of 10 solar masses at the event horizon. (Use G = 6.67 × 10⁻¹¹ N·m²/kg², 1 solar mass = 2 × 10³⁰ kg).

Answer: Potential Energy = -G * M * m / r; where M = 2 × 10³¹ kg, m = 2 × 10³⁰ kg, r ≈ 3 km (3 × 10³ m). Calculation: - (6.67 × 10⁻¹¹) * (2 × 10³¹) * (2 × 10³⁰) / (3 × 10³) = -8.89 × 10⁴⁸ Joules.

Question 6: Identify the main elements involved in the formation of a star from a nebula.

Answer: Hydrogen and helium are the main elements involved in star formation from a nebula.

Question 7: What is a supernova and how does it relate to the formation of black holes?

Answer: A supernova is the explosion of a massive star at the end of its life, which can leave behind a dense core that may collapse into a black hole.

Question 8: Explain why a black hole has such a strong gravitational pull.

Answer: Because a black hole's mass is concentrated into a very small area, resulting in an extremely high density and gravitational pull according to Einstein's theory of general relativity.

Question 9: Identify one way in which understanding the life cycle of stars can benefit scientific research or technology.

Answer: Studying star life cycles helps improve our understanding of cosmic phenomena, which can influence advancements in space exploration technology and astrophysics models.

Question 10: Describe the safety precautions scientists must consider when studying high-energy astrophysical phenomena such as black holes.

Answer: Scientists must consider radiation hazards, ensure proper shielding and remote sensing techniques, and follow strict safety protocols when handling equipment or data related to high-energy phenomena like black holes, to prevent exposure to harmful radiation and ensure accurate data collection.