PH2080 – Introduction to Theoretical
Astrophysics (Physik)Comprehensive Practice
Examination (2026–2027 Edition)Latest
Curriculum Alignment | Graduate-Level
Difficulty | Multiple Choice | Verified Answers
| Detailed Rationales
1. Which physical law primarily explains why planets remain
in stable elliptical orbits around the Sun?
A. Maxwell's Equations
B. Newton's Law of Universal Gravitation
C. Planck's Radiation Law
D. Stefan-Boltzmann Law
Answer: B
Rationale: Newton's universal law of gravitation, together with
Newton's laws of motion, explains planetary motion. Kepler's
laws emerge naturally from Newtonian gravitation.
,2. Which quantity remains constant for an isolated stellar
system?
A. Luminosity
B. Radius
C. Total Energy
D. Surface Temperature
Answer: C
Rationale: In an isolated system, total energy is conserved
although it may change form between kinetic, potential, and
thermal energy.
3. A perfect blackbody emits radiation described by
A. Wien's Approximation
B. Rayleigh Scattering
C. Planck's Law
D. Rutherford's Formula
Answer: C
Rationale: Planck's law accurately describes the spectral energy
distribution of an ideal blackbody.
,4. The peak wavelength of blackbody radiation decreases as
temperature increases according to
A. Hubble's Law
B. Wien's Displacement Law
C. Hooke's Law
D. Coulomb's Law
Answer: B
Rationale: Wien's law states that hotter objects emit peak
radiation at shorter wavelengths.
5. The dominant fusion process inside the Sun is
A. Triple-alpha Process
B. Carbon Burning
C. Proton-Proton Chain
D. Oxygen Burning
Answer: C
Rationale: Stars with masses comparable to the Sun primarily
generate energy through the proton-proton chain.
, 6. Hydrostatic equilibrium in stars represents a balance
between
A. Radiation and Magnetism
B. Gravity and Internal Pressure
C. Nuclear Force and Gravity
D. Rotation and Luminosity
Answer: B
Rationale: Stars remain stable because inward gravitational
forces are balanced by outward pressure.
7. Which stellar remnant is supported primarily by electron
degeneracy pressure?
A. Neutron Star
B. White Dwarf
C. Black Hole
D. Protostar
Answer: B
Astrophysics (Physik)Comprehensive Practice
Examination (2026–2027 Edition)Latest
Curriculum Alignment | Graduate-Level
Difficulty | Multiple Choice | Verified Answers
| Detailed Rationales
1. Which physical law primarily explains why planets remain
in stable elliptical orbits around the Sun?
A. Maxwell's Equations
B. Newton's Law of Universal Gravitation
C. Planck's Radiation Law
D. Stefan-Boltzmann Law
Answer: B
Rationale: Newton's universal law of gravitation, together with
Newton's laws of motion, explains planetary motion. Kepler's
laws emerge naturally from Newtonian gravitation.
,2. Which quantity remains constant for an isolated stellar
system?
A. Luminosity
B. Radius
C. Total Energy
D. Surface Temperature
Answer: C
Rationale: In an isolated system, total energy is conserved
although it may change form between kinetic, potential, and
thermal energy.
3. A perfect blackbody emits radiation described by
A. Wien's Approximation
B. Rayleigh Scattering
C. Planck's Law
D. Rutherford's Formula
Answer: C
Rationale: Planck's law accurately describes the spectral energy
distribution of an ideal blackbody.
,4. The peak wavelength of blackbody radiation decreases as
temperature increases according to
A. Hubble's Law
B. Wien's Displacement Law
C. Hooke's Law
D. Coulomb's Law
Answer: B
Rationale: Wien's law states that hotter objects emit peak
radiation at shorter wavelengths.
5. The dominant fusion process inside the Sun is
A. Triple-alpha Process
B. Carbon Burning
C. Proton-Proton Chain
D. Oxygen Burning
Answer: C
Rationale: Stars with masses comparable to the Sun primarily
generate energy through the proton-proton chain.
, 6. Hydrostatic equilibrium in stars represents a balance
between
A. Radiation and Magnetism
B. Gravity and Internal Pressure
C. Nuclear Force and Gravity
D. Rotation and Luminosity
Answer: B
Rationale: Stars remain stable because inward gravitational
forces are balanced by outward pressure.
7. Which stellar remnant is supported primarily by electron
degeneracy pressure?
A. Neutron Star
B. White Dwarf
C. Black Hole
D. Protostar
Answer: B
