ASP MCQ 4

Question 1

What is a pulsar?

Accepted Answer

A rapidly rotating neutron star emitting beams of electromagnetic radiation

Answer

A pulsar is a highly magnetized, rapidly rotating neutron star whose beamed radiation sweeps past Earth like a lighthouse, producing regular pulses.

Question 2

In spectroscopy, what does the presence of dark absorption lines in a star's spectrum indicate?

Accepted Answer

Elements in the star's atmosphere absorbing specific wavelengths

Answer

Absorption lines form when cooler atmospheric gases absorb specific photon energies from the continuous spectrum emitted below, revealing the star's elemental composition.

Question 3

What is the approximate age of the universe according to current cosmological models?

Accepted Answer

13.8 billion years

Answer

Based on CMB observations and the Hubble constant, the universe is estimated to be approximately 13.8 billion years old.

Question 4

Which process produces the energy radiated by main sequence stars like our Sun?

Accepted Answer

Proton-proton chain fusion of hydrogen into helium

Answer

In solar-mass stars, the proton-proton chain dominates, fusing hydrogen nuclei into helium and releasing enormous energy as photons and neutrinos.

Question 5

What is the event horizon of a black hole?

Accepted Answer

The boundary within which escape velocity exceeds the speed of light

Answer

The event horizon is the spherical surface around a black hole's singularity at which escape velocity equals the speed of light — nothing inside can escape.

ASP - Astronomical Society of the Pacific Exam Practice Test

ASP - Astronomical Society of the Pacific Exam Practice Test

ASP MCQ 4