Black holes are an enormous amount of matter packed into a minimal area; it is one of the strangest concepts in the universe. Since an assembly of massive hydrogen atoms forms a star, hydrogen atoms in their core release tremendous energy as they fuse into helium. The liberated energy maintains a delicate balance between the two forces as it is in the form of radiation and pushes against gravity.
Black holes can be big or small. The smallest black holes in the universe are as small as an atom. These black holes are very small but have the mass of a big mountain.
Another kind of black hole whose mass can be up to 20 times more than the mass of the Sun is called “stellar.” There may be many, many stellar mass black holes in Earth’s galaxy.
The black holes that have masses that are more than 1 million suns together are the largest black holes are called “supermassive.” Every large galaxy contains a supermassive black hole at its centre, and scientists have proved it. At the centre of the Milky Way galaxy, the supermassive black hole is known as Sagittarius.
Important Questions on Black Holes
1) The branch of science that deals with the universe’s formation are known as _______.
a) Earth science
b) Zoology
c) Cosmology
d) Space science
Correct Option: (c)
Explanation: From the big band theory and with the ultimate fate of the universe, the branch of science that concerns the creation of the universe is known as Cosmology.
2) Much of the universe’s mass consists of dark energy; this evidence has come from which of the following statements?
a) Observing enormously distant supernovae
b) Determining the distance to quasars
c) Determining the distance to the Coma cluster
d) Measurement of the density of matter in the solar system
Correct Option: (a)
Explanation: When a massive star dies, Supernovae are created. Supernovae are at a very large distance; by observing this, we have got the indication that the universe covers a majority of dark matter.
3) Which among the following statements is not an allegation of Hubble’s law?
a) The universe is expanding continuously
b) The universe had a beginning
c) Earth is in the centre of the universe
d) None of these
Correct Option: (c)
Explanation: The universe is expanding; Hubble has stated this. It also indicates that the universe was once denser than it is now, which means that the universe had a beginning. But the Earth is at the centre of the universe has not been stated in this law.
4) The age of the universe is approximately _____.
a) 2 billion years
b) 20 billion years
c) 200 billion years
d) 10 billion years
Correct Option: (d)
Explanation: Studies about the universe say that the universe is always expanding continuously for 10 billion years now.
5) Which among the following is the universe’s rate of expansion?
a) Zero
b) Constant
c) Accelerating
d) Decelerating
Correct Option: (c)
Explanation: It’s the dark energy that dominates the universe. This means that the rate of the expansion of the universe is accelerating.
6) Which of the following processes happens inside a star?
a) Nuclear fission
b) Diffusion
c) Electron excitation
d) Nuclear fusion
Correct Option: (d)
Explanation: The stars undergo nuclear fusion throughout their lives. To forge heavier elements, hydrogen and helium atoms fuse.
7) What would the Earth’s sun change into when it dies?
a) Nebula
b) Supernova
c) Red giant
d) White dwarf
Correct Option: (c)
Explanation: In the universe, the sun is a massive star. Therefore, it would swell up into a red giant when it dies; also, it would slough off its outer layers.
8) What will happen in a star when its hydrogen fuel ends up?
a) It will contract
b) It will expand
c) The star will explode
d) The star will stop shining
Correct Option: (a)
Explanation: The star contracts under the gravitational force when its fuel ends up. Enough energy is created to use helium as fuel when it contracts.
9) What are Black holes?
Black holes are an enormous amount of matter packed into a minimal area; it is one of the strangest concepts in the universe. Black holes are a collection of a very strong gravitational field that even light can’t escape through them. They are invisible since; no light can get out of them. Special tools and space telescopes are required to find a black hole. These special tools help us observe how stars act differently than the other stars when they come close to the black hole.
10) What are the different types of black holes?
There are four types of black holes:
- Stellar
- Intermediate
- Supermassive
- Miniature
Practice Questions
1) What is a black hole?
2) Explain the formation of black holes.
3) Name the types of black holes.
4) What do you mean by gravitation?
5) What is the Universal law of gravitation?
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