PH2080 – Introduction to Astrophysics (Physik
Master)Comprehensive Practice Examination
(2026–2027 Edition)Graduate-Level Multiple
Choice Questions | Verified Answers |
Detailed Rationales in Italics
Question 1
Which physical process primarily powers a main-sequence star
like the Sun?
A. Triple-alpha fusion
B. Carbon burning
C. Proton–proton chain fusion
D. Electron capture
Answer: C
Rationale: Stars with masses similar to the Sun generate energy
primarily through the proton–proton chain, converting
hydrogen into helium while releasing energy according to
Einstein's mass–energy relation.
,Question 2
According to the Virial Theorem, a gravitationally bound stellar
system satisfies
A. 2K = U
B. 2K + U = 0
C. K = U
D. K + U = 0
Answer: B
Rationale: The Virial Theorem states that twice the total kinetic
energy plus the gravitational potential energy equals zero for
systems in dynamical equilibrium.
Question 3
The Schwarzschild radius depends directly upon
A. Density
B. Temperature
C. Mass
D. Luminosity
,Answer: C
Rationale: The Schwarzschild radius is proportional only to mass
and defines the event horizon of a non-rotating black hole.
Question 4
Which quantity remains approximately constant during the
gravitational collapse of an isolated molecular cloud?
A. Radius
B. Density
C. Temperature
D. Angular momentum
Answer: D
Rationale: Conservation of angular momentum causes
collapsing clouds to rotate faster, ultimately forming
protostellar disks.
Question 5
Dark matter was first strongly inferred from observations of
A. Solar oscillations
, B. Pulsars
C. Galaxy rotation curves
D. White dwarfs
Answer: C
Rationale: Spiral galaxies exhibit flat rotation curves at large
radii, implying the presence of unseen mass beyond visible
stars.
Question 6
The Chandrasekhar Limit represents the maximum mass of
A. Neutron stars
B. White dwarfs
C. Brown dwarfs
D. Red giants
Answer: B
Rationale: Electron degeneracy pressure supports white dwarfs
only up to approximately 1.4 solar masses.
Question 7
Master)Comprehensive Practice Examination
(2026–2027 Edition)Graduate-Level Multiple
Choice Questions | Verified Answers |
Detailed Rationales in Italics
Question 1
Which physical process primarily powers a main-sequence star
like the Sun?
A. Triple-alpha fusion
B. Carbon burning
C. Proton–proton chain fusion
D. Electron capture
Answer: C
Rationale: Stars with masses similar to the Sun generate energy
primarily through the proton–proton chain, converting
hydrogen into helium while releasing energy according to
Einstein's mass–energy relation.
,Question 2
According to the Virial Theorem, a gravitationally bound stellar
system satisfies
A. 2K = U
B. 2K + U = 0
C. K = U
D. K + U = 0
Answer: B
Rationale: The Virial Theorem states that twice the total kinetic
energy plus the gravitational potential energy equals zero for
systems in dynamical equilibrium.
Question 3
The Schwarzschild radius depends directly upon
A. Density
B. Temperature
C. Mass
D. Luminosity
,Answer: C
Rationale: The Schwarzschild radius is proportional only to mass
and defines the event horizon of a non-rotating black hole.
Question 4
Which quantity remains approximately constant during the
gravitational collapse of an isolated molecular cloud?
A. Radius
B. Density
C. Temperature
D. Angular momentum
Answer: D
Rationale: Conservation of angular momentum causes
collapsing clouds to rotate faster, ultimately forming
protostellar disks.
Question 5
Dark matter was first strongly inferred from observations of
A. Solar oscillations
, B. Pulsars
C. Galaxy rotation curves
D. White dwarfs
Answer: C
Rationale: Spiral galaxies exhibit flat rotation curves at large
radii, implying the presence of unseen mass beyond visible
stars.
Question 6
The Chandrasekhar Limit represents the maximum mass of
A. Neutron stars
B. White dwarfs
C. Brown dwarfs
D. Red giants
Answer: B
Rationale: Electron degeneracy pressure supports white dwarfs
only up to approximately 1.4 solar masses.
Question 7
