Physics · General Awareness

Astrophysics and Cosmology

1,746 Questions

Delve into the mysteries of the universe with questions on black holes, gravitational waves, and spacetime concepts. Topics include the event horizon, the LIGO experiment, and mathematical techniques used in Twistor Theory. These advanced physics concepts are frequently tested in science optional papers.

Black hole physicsGravitational waves and lensingGeneral relativity principlesElectromagnetic spectrum regionsCosmological phenomena

Astrophysics and Cosmology Questions

Multiple choice

Which of the following discoveries did Albert Einstein discover?

  1. Gravitation

  2. Relativity

  3. X-rays

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

Albert Einstein is famous for his theory of relativity, which fundamentally changed our understanding of space, time, and gravity. Gravitation was described by Newton, X-rays by Roentgen, and radioactivity by Becquerel.

Multiple choice

The black hole nearest to the Earth named V4641 is visible. How?

  1. Because it is wrongly believed to be a black hole

  2. Because it still has traces of hydrogen

  3. Because of the star that orbits around it

  4. Because of the heat emitted by it
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

At first, scientists believed that the nearest black hole to the Earth was the one at the center of the Milky Way Galaxy. This seemed to be debunked by the discovery of a new black hole only 1600 light years away. This new black hole is actually a rare type of black hole called a micro quasar. This new black hole has been named V4641 Sgr since it is located in the Sagittarius arm of the Milky Way. The reason it is visible is because of the star that orbits it. The gases of this star are steadily being absorbed by this black hole. These gases emit radiation that can be detected by Earth’s telescopes.

Multiple choice lorentz transformation and muon experiment option a: relativity physics
We don't observe space contraction in our every day lives and the reason is

  1. Space contraction is not noticeable until objects approach the speed of light.

  2. Space contraction does not occur until objects approach the speed of light.

  3. Space contraction only occurs in a vacuum.

  4. Space contraction is offset by the effect of gravity.

  5. Acceleration is necessary for length contraction.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The contracted length of objects moving relative to an observer with speed $v$ is given by $l'=l _0\sqrt{1-(\dfrac{v}{c})^2}$.

Hence at small speeds $v<<c$, $l'\approx l _0$, and hence the space contraction is not noticeable.

Multiple choice physics life cycle of stars evolution and end stages of stars the stars stars

Which of the following statements about degeneracy pressure is not true?

  1. Degeneracy pressure varies with the temperature of the star.

  2. Degeneracy pressure can halt gravitational contraction of a star even when no fusion is occurring in the core.

  3. Degeneracy pressure keeps any protostar less than 0.08 solar mass from becoming a true, hydrogen-fusing star.

  4. Degeneracy pressure supports white dwarfs against gravity.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Degeneracy pressure is the pressure which prevent the neutron star from becoming the Black hole.

Degeneracy pressure does not varies with the temperature of the star.

Multiple choice physics life cycle of stars evolution and end stages of stars the stars stars

What happens after a helium flash?

  1. The core quickly heats up and expands.

  2. The star breaks apart in a violent explosion.

  3. The core suddenly contracts.

  4. The core stops fusing helium.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A helium flash is a very brief thermal runaway nuclear fusion of large quantities of helium into carbon through the triple-alpha process in the core of low mass stars (between 0.8 solar masses ( M ) and 2.0 M ) during their red giant phase . This results in heating up the core and expansion of the core takes place as a result

Multiple choice physics gravitation tides movements of ocean and sea water circulation of ocean water

The type of Gravitational Force that causes tides is known as:

  1. Nuclear Force

  2. Tractive Force

  3. Tidal Force

  4. Wave Force
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Tides are caused by the combined gravitation attraction of the Sun and Moon on the Earth. Force that results in a motion between a body and a tangential surface is called a tractive force.

Multiple choice physics universe and space xx radio telescope and space telescopes optical instruments : telescope

Which among the following is not true for Hubble ST?

  1. Hubbles observations found that black holes are common to the centers of all galaxies.

  2. Hubble's Telescope was first to found the traces of water on Earth.

  3. Hubble Deep field and Hubble Ultra Deep Field images reveal galaxies that are billions of light-years away.

  4. Astronauts used the telescope to observe distant supernovae.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

We know that Earth has water, blue planet, 71% of Earth's surface is covered in water. Hubble telescope was definitely not the first to found the traces of water on Earth. 

Multiple choice physics our solar system planets of the solar system solar system and sun introduction to solar system

Degenerate electron pressure will not be sufficient to prevent the core collapse of white dwarf if its mass becomes n times of our solar mass. Value of n is:

  1. 0.5

  2. 0.8

  3. 1

  4. 1.4
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This is the definition of Chandrasekhar's Limit . 
Degenerate electron pressure will not be sufficient to prevent core collapse of white dwarf if its mass becomes 1.4 times or more of our solar mass.