Physics · Science General

Astronomy and Cosmology

4,498 Questions

This topic provides questions on astronomy, cosmology, and the physical universe. It covers subjects like the Hubble sequence, constellations, dark matter, and stellar evolution. These questions help build a strong foundation for general science exam sections.

Galaxies and clustersConstellations and starsStellar evolutionSpace observatories

Astronomy and Cosmology Questions

Multiple choice

Which sort of star is the sun?

  1. Supergiant

  2. Red giant

  3. Main sequence

  4. White dwarf
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The Sun is classified as a G-type main-sequence star. It is currently in the stable phase of its life cycle, where it fuses hydrogen into helium.

Multiple choice stefan's law black body radiation heat transfer thermal properties physics

In the Orion stellar system the shining of a star is $17\space \times 10^3$ times that of the sun. If the temperature of the surface of the sun $6 \times 10^3 K$ then the temperature of this star will be

  1. 273 K

  2. 652 K

  3. 6520 K

  4. 68520 K
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The power radiated is directly proportional to the fourth power of the absolute temperature.
$P \propto T^{4}$
$P = kT^{4}$ 

Let P = Power radiated by the sun
Power radiated by star $ = 17 \times  10^{3}P $
$\dfrac{T _{star}^{4}}{T _{sun}^{4}} = 17 \times  10^{3}$

$\dfrac{T _{star}}{T _{sun}} = 11.418$

$T _{star} = 6000 \times  11.418 = 68,511K$

Hence, the answer is option D.

Multiple choice physics electromagnetic waves properties and uses of different radiation electromagnetic spectrum spectrum

What name is given to the type of astronomy having the following characteristics.
I. It is carried out in the waveband $300$nm to $10$nm.
II. The atmosphere is opaque to the incoming radiation from space
III. Observations are to be carried out from above the earth's atmosphere.

  1. X-ray astronomy

  2. Ultra-violet astronomy

  3. Infra-red astronomy

  4. Gamma ray astronomy
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Ultra-violet astronomy is carried out in waveband of $10nm-300nm$ in which is above earth's atmosphere.
Multiple choice

Which of the following is not a characteristic used to classify stars?

  1. Mass

  2. Temperature

  3. Luminosity

  4. Color
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Color is not a fundamental property used to classify stars. Instead, stars are classified based on their mass, temperature, and luminosity.

Multiple choice

What is the main source of energy in stars?

  1. Nuclear Fusion

  2. Gravitational Contraction

  3. Chemical Reactions

  4. Radioactive Decay
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Stars generate energy through nuclear fusion reactions, where lighter elements are combined to form heavier elements, releasing vast amounts of energy.

Multiple choice

Which type of star is the most common in the universe?

  1. Red Dwarfs

  2. White Dwarfs

  3. Neutron Stars

  4. Black Holes
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Red dwarfs are the most common type of star, making up about 85% of all stars in the Milky Way galaxy.

Multiple choice

What is the final stage in the evolution of a massive star?

  1. Supernova

  2. Neutron Star

  3. Black Hole

  4. White Dwarf
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Massive stars end their lives in a supernova explosion, which can be so powerful that it can outshine an entire galaxy.

Multiple choice

What is the remnant left behind after a supernova explosion?

  1. Neutron Star

  2. Black Hole

  3. White Dwarf

  4. Red Giant
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

If the core of a massive star is sufficiently massive, it collapses into a neutron star after a supernova explosion.

Multiple choice

What is the fate of a low-mass star like our Sun?

  1. Supernova

  2. Neutron Star

  3. Black Hole

  4. White Dwarf
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Low-mass stars like our Sun end their lives as white dwarfs, which are dense remnants that have exhausted their nuclear fuel.

Multiple choice

What is the main sequence on the Hertzsprung-Russell diagram?

  1. A region where stars are fusing hydrogen in their cores

  2. A region where stars are fusing helium in their cores

  3. A region where stars are fusing carbon in their cores

  4. A region where stars are fusing oxygen in their cores
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The main sequence on the Hertzsprung-Russell diagram represents stars that are fusing hydrogen in their cores, which is the longest and most stable phase of a star's life.

Multiple choice

What is a red giant?

  1. A star that has exhausted its hydrogen fuel and is fusing helium in its core

  2. A star that has exhausted its helium fuel and is fusing carbon in its core

  3. A star that has exhausted its carbon fuel and is fusing oxygen in its core

  4. A star that has exhausted its oxygen fuel and is fusing silicon in its core
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A red giant is a star that has exhausted its hydrogen fuel and is now fusing helium in its core, causing it to expand and become cooler.

Multiple choice

What is a white dwarf?

  1. A star that has exhausted its hydrogen and helium fuel and has collapsed under its own gravity

  2. A star that has exhausted its hydrogen and helium fuel and has expanded into a red giant

  3. A star that has exhausted its hydrogen and helium fuel and has exploded as a supernova

  4. A star that has exhausted its hydrogen and helium fuel and has become a neutron star
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A white dwarf is a dense remnant of a star that has exhausted its hydrogen and helium fuel and has collapsed under its own gravity.

Multiple choice

What is a neutron star?

  1. A star that has exhausted its hydrogen and helium fuel and has collapsed under its own gravity

  2. A star that has exhausted its hydrogen and helium fuel and has expanded into a red giant

  3. A star that has exhausted its hydrogen and helium fuel and has exploded as a supernova

  4. A star that has exhausted its hydrogen and helium fuel and has become a white dwarf
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A neutron star is a dense remnant of a star that has exhausted its hydrogen and helium fuel and has collapsed under its own gravity, resulting in a core composed primarily of neutrons.

Multiple choice

What is the name of the galaxy that contains our solar system?

  1. Andromeda Galaxy

  2. Milky Way Galaxy

  3. Sombrero Galaxy

  4. Pinwheel Galaxy
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The Milky Way Galaxy is a barred spiral galaxy that contains our solar system. It is estimated to be about 13.6 billion years old and has a diameter of about 100,000 light-years.