ASP MCQ 3 — Questions and Answers
Question 1: Which type of galaxy is characterized by a central bulge, spiral arms, and a disk of stars and gas?
- Elliptical
- Irregular
- Spiral (Correct answer)
- Lenticular
Correct answer: Spiral
Spiral galaxies feature a central bulge surrounded by a flat disk with curved spiral arms containing young stars, gas, and dust.
Question 2: What is the Chandrasekhar limit in stellar astrophysics?
- The maximum mass of a neutron star (~3 solar masses)
- The maximum mass of a white dwarf (~1.4 solar masses) (Correct answer)
- The minimum mass for nuclear fusion (~0.08 solar masses)
- The mass at which a star becomes a red giant (~0.5 solar masses)
Correct answer: The maximum mass of a white dwarf (~1.4 solar masses)
The Chandrasekhar limit (~1.4 solar masses) is the maximum mass a white dwarf can have before electron degeneracy pressure can no longer support it.
Question 3: Which force primarily drives the formation of stars from interstellar gas clouds?
- Electromagnetic force
- Nuclear strong force
- Gravitational force (Correct answer)
- Weak nuclear force
Correct answer: Gravitational force
Gravity causes regions of a gas cloud to collapse inward; as density and temperature rise, nuclear fusion eventually ignites a new star.
Question 4: What does the cosmic microwave background (CMB) radiation represent?
- Radiation from active galactic nuclei
- Afterglow light from the Big Bang about 380,000 years after it occurred (Correct answer)
- Synchrotron radiation from pulsars
- Thermal emission from dust in the Milky Way
Correct answer: Afterglow light from the Big Bang about 380,000 years after it occurred
The CMB is the relic thermal radiation from when the universe cooled enough for atoms to form, releasing photons that now permeate all of space.
Question 5: What unit is commonly used to measure distances within our solar system?
- Light-year
- Parsec
- Astronomical unit (AU) (Correct answer)
- Angstrom
Correct answer: Astronomical unit (AU)
One astronomical unit (AU) equals the average Earth-Sun distance (~150 million km) and is the standard measure for intra-solar-system distances.
Question 6: Which planet has the largest number of confirmed moons in our solar system?
- Jupiter
- Saturn (Correct answer)
- Uranus
- Neptune
Correct answer: Saturn
Saturn holds the record for the most confirmed moons, surpassing Jupiter after recent discoveries of many small irregular moons.
Question 7: What is stellar parallax used to measure?
- A star's surface temperature
- The distance to nearby stars (Correct answer)
- A star's chemical composition
- A star's rotational period
Correct answer: The distance to nearby stars
Stellar parallax measures the apparent shift of a nearby star against distant background stars as Earth orbits the Sun, yielding the star's distance.
ASP MCQ 3
Which type of galaxy is characterized by a central bulge, spiral arms, and a disk of stars and gas?