Practice Test GeeksASP - Astronomical Society of the Pacific Exam Practice Test
← All ASP Flashcard Decks

Astrophysics Fundamentals Flashcards

6 cards from real ASP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 6 Astrophysics Fundamentals flashcards as text

  1. What is the Schwarzschild radius?

    Answer: The critical radius at which an object becomes a black hole (its escape velocity equals the speed of light)

    The Schwarzschild radius is the radius to which a mass must be compressed to form a black hole, where the escape velocity equals the speed of light (rs = 2GM/c²); for the Sun it is about 3 km.

  2. What is nuclear binding energy?

    Answer: The energy required to completely separate the nucleons (protons and neutrons) in an atomic nucleus

    Nuclear binding energy is the energy required to disassemble an atomic nucleus into its constituent protons and neutrons; fusion of lighter elements releases energy when the products have higher binding energy per nucleon.

  3. What is the mass-luminosity relationship for main-sequence stars?

    Answer: L ∝ M³·⁵ to M⁴ (approximately)

    For main-sequence stars, luminosity scales approximately as L ∝ M³·⁵ to M⁴, meaning a star twice as massive as the Sun is roughly 10–16 times more luminous and consequently lives much shorter.

  4. What is escape velocity?

    Answer: The minimum velocity needed for an object to escape a body's gravitational pull without further propulsion

    Escape velocity is the minimum speed an object needs to escape a gravitational field without additional thrust, equal to v = √(2GM/r); for Earth it is about 11.2 km/s.

  5. What is the hydrostatic equilibrium condition in stars?

    Answer: The balance between the inward gravitational force and the outward pressure gradient that keeps a star stable in size

    Hydrostatic equilibrium is the condition where the outward pressure gradient force (thermal + radiation pressure) exactly balances the inward gravitational force at every point within a star, maintaining a stable structure.

  6. What is the Eddington luminosity?

    Answer: The maximum luminosity at which radiation pressure balances gravity, above which material is blown away

    The Eddington luminosity is the theoretical maximum luminosity at which the outward radiation pressure force exactly balances the inward gravitational force, with more luminous sources blowing away accreting material.