RBSE Solutions for Class 6 Social Science Chapter 1 Our Universe is part of RBSE Solutions for Class 6 Social Science. Here we have given Rajasthan Board RBSE Class 6 Social Science Chapter 1 Our Universe.
| Board | RBSE |
| Textbook | SIERT, Rajasthan |
| Class | Class 6 |
| Subject | Social Science |
| Chapter | Chapter 1 |
| Chapter Name | Our Universe |
| Number of Questions | 41 |
| Category | RBSE Solutions |
Rajasthan Board RBSE Class 6 Social Science Chapter 1 Our Universe
Textbook Activity Based Questions and Answers
Question 1.
Observe the stars in night and find out the position of Saptarishi Mandal in the sky. (Page 3)
Answer:
By observing the stars after sunset, it is found that’the position of Saptarishi Mandal in the sky is towards the northern direction.
Question 2.
Ask your parents to tell conversational stories about stars and note them in your notebook.
Answer:
- Conversational stories heard from the elder members of our family tell that earlier there was a prince called Dhruv, who was removed by his father from his lap, as he was told to do so by his second wife. Due to this, Dhruv became sad and went into the jungle and started praying to God to let him sit in his lap. Finally, he was blessed by Go that he would attain the highest place. Due to the same reason, Dhruv is still visible to us in the form of Pole star (Dhruv Tara).
- The elders of the family say that the stars which are present in the sky are our elders who are visible in the form of stars after their death.
- The elders of the family interpret the moon as ‘Chandamama’.
Question 3.
Recognize the shape of group of stars and try to name these celestial bodies.
Answer:
When we look at the stars during the night, we find shapes such as cot, deer, bear, kettle without arm, tillage plough, lightened small bulbs, etc.
Question 4.
Is the expansion of the universe and the galaxies increasing? Explain the distance between with examples. (Page 6)
Answer:
The galaxies are moving away from one another. Due to this, the universe is also expanding. This can be clarified with the help of a balloon. Take a balloon and mark two or more than two spots on it. Now inflate the balloon with air. We will observe that while inflating, the spots on it are moving away from one another. Likewise, all the galaxies are moving away from one another. Do you know? (Page 5)
Question 1.
What is light year?
Answer:
Light year is a measuring unit of distance. This is used to calculate distance between heavenly bodies. Light travels at a tremendous speed of about 3,00,000 kms per second. And the distance that the light travels in a year is called a light year (LY). Thus, the light travels 95 billion kms in a year and so this distance is known as a light year.
Textbook Exercise
Question 1.
Choose the correct option
(i) A star shines
(a) through its own light
(b) through the light of others
(c) through the light of the moon
(d) through the light of the planets
Answer:
(a) through its own light
(ii) The direction denoted by the Pole star is
(a) North
(b) South
(c) East
(d) West
Answer:
(a) North
Question 2.
Match the following heavenly bodies with their significance
| Heavenly Body | Significance |
| i. The Sim | a. A planet |
| ii. A Comet | b. A large group of millions of galaxies |
| iii. The Earth | c. A star |
| iv. The Universe | d. A large group of millions of stars |
| v. A Galaxy | e. A tail star |
Answer:
(i) c, (ii) e, (iii) a, (iv) b, (v) d
Question 3.
Fill in the blanks
1. The group of seven stars seen in India is named as ……………….. .
2. All the planets and the satellites illuminate due to the light of the ………………. .
3. …………………. is the nearest star to the Earth.
4. Different …………….. are located inside various nakshatramandals.
Answer:
1. Saptarishimandal
2. Sun
3. The sun
4. Tarkiya Mandals
Question 4.
What is Hailey’s comet? Describe its characteristics.
Answer:
Hailey’s comet is the most popular tail star. It appears after a long interval of 76 years. It was last seen in the year 1986. Now it will be again seen in the year 2062.
Question 5.
What are celestial bodies? What are they formed of?
Answer:
All the stars, meteors, planets, satellites, comets, including our earth, the sun and the moon, which remain scattered in the sky are called the celestial bodies. Stars are formed by the collision of helium and hydrogen atoms. Stars are gaseous in form. But, all the celestial bodies are not gaseous. Some bodies are made of solid substances, while some bodies are made of solid, liquid and gaseous substances.
Question 6.
How and when was the universe originated?
Answer:
Many theories have been presented and propounded in context to the origin of the universe, but the most accepted theory in present time is the ‘Big Bang’ theory. According to this theory, about 13.7 billion years ago, an explosion took place in the space which is called a big bang. After this explosion, the universe and the celestial bodies were produced.
Question 7.
What is a galaxy? Explain.
Answer:
Different stars and their remnants, gases between them and deposition of dust particles between them are tied together due to the gravitational force in space and they are called galaxies. These galaxies flourish in length and breadth in many lacks of light years.
Question 8.
Why can’t we see the twinkling stars of night in the day time?
Answer:
During the night, many stars can be seen twinkling in the sky, but they disappear during the day, because the Sun is a star situated near the Earth, while the other stars are far away from the Earth. Due to this, the light of the sun is more intense while the light of other stars is negligible, and therefore, due to the effect of their light being very less during the presence of the sun, stars are not seen during daytime.
Question 9.
Explain the ‘Big bang’ theory.
Answer:
Big bang theory is the most accepted theory of evolution of the universe. According to this theory, the universe evolved due to the explosion which took place around 13.7 billion years ago. Various celestial bodies were produced by the substances which were emitted by the explosion. Due to the deposit of these substances around the bodies, they increased in size and several galaxies were formed, due to which, the universe started expanding. Since the time of its formation, the universe is continuously expanding.
Other Important Questions
Objective Type Questions
Question 1.
Our Earth is a
(a) star
(b) planet
(c) satellite
(d) meteorite
Answer:
(b) planet
Question 2.
Light Year is a measure of
(a) time
(b) weight
(c) pressure
(d) distance
Answer:
(d) distance
Question 3.
Eravat Path is the name of
(a) the universe
(b) the space
(c) a star
(d) the milky way
Answer:
(d) the milky way
Question 4.
Hailey’s comet is visible
(a) after every 50 years
(b) after every 75 years
(c) after every 76 years
(d) after every 86 years
Answer:
(c) after every 76 years
Fill in the blanks
1. The Pole Star always remains ………………. in its place.
2. Traditional tales and stories were imaginary, so they are known as …………………… .
3. According to Hindu religious texts, the Pole Star is known as ………………………. .
4. The group of countless galaxies is known as …………………. .
Answer:
1. firm
2. myth
3. Dhruv Tara
4. universe.
Very Short Answer Type Questions
Question 1.
What is meant by constellation of stars or nakshatramandal?
Answer:
The group of stars visible in some shape in the sky is known as constellation of stars or nakshatramandal.
Question 2.
What is “Charpai”?
Answer:
Four stars included in the group of Saptarishi Mandal is known as ‘Charpai’ in many parts of India.
Question 3.
In various countries, what are the names used to signify “Charpai”?
Answer:
In France, it is recognized as a ‘sauce pan’, in Britain, it is called a ‘plough’ and in Greece, it is called a ‘small bear’.
Question 4.
What is a myth?
Answer:
In ancient times, the authenticity of some statement was proved on the basis of imaginary fables. The same imaginary tales and stories are known as myths.
Question 5.
What is the literary meaning of the term ‘Dhruv Tara’?
Answer:
In Hindu mythological texts, the ‘Pole Star’ is considered as ‘Dhruv Tara’. Its literary meaning is immovable or firm star.
Question 6.
Who were the parents of Dhruv?
Answer:
Dhruv was the son of king Uttanpaad and queen Suniti.
Question 7.
Why do stars present in the sky appear to be small?
Answer:
The major reason for the stars appearing to be small is that they are situated at very far away from the Earth.
Question 8.
How do the planets and the satellites shine?
Answer:
All the planets and the satellites shine through the light of the Sun.
Question 9.
What is space?
Answer:
Various celestial bodies appear to be scattered in the infinite sky. This infinite sky is known as space.
Question 10.
What is light year?
Answer:
Light year is a measuring unit of distance. The distance which light covers in one year is known as light year.
Question 11.
How much distance does light cover in one year and what is its speed?
Answer:
Light covers a distance of around 95 hundred billion kms in one year and its speed is around 3 lakh kms per second.
Question 12.
What is the meaning of ‘galaxy’ and ‘universe’?
Answer:
Countless groups of celestial bodies scattered in the infinite sky is known as galaxy and the group of countless galaxies is known as universe.
Question 13.
In which galaxy is our solar system situated?
Answer:
Our solar system is situated in a galaxy named ‘Eravat Path’. It is also known as ‘Mandakini’ or Milky way.
Question 14.
Which is the nearest star to the earth and what is its distance from the earth?
Answer:
The Sun is the nearest star to the earth and it is situated at a distance of around 15 crore kms from the earth.
Question 15.
Why is Comet called the tail star?
Answer:
The gaseous substances present in comet have a very high velocity, which form a tail-like structure, therefore this is known as tail star.
Short Answer Type Questions
Question 1.
Why were fictitious names assigned to stars and planets during ancient times?
Answer:
In ancient times, mankind lacked in modem technology, due to which, there was no other option present to see these stars and planets except without blinking the eyes. Due to this, they were assigned fictitious names in order to identify them.
Question 2.
How was the naming of Milky Way done?
Answer:
In fact, Milky Way is a group of stars. This group is illuminative. Due to this condition, it was presumed in ancient India, that it is the river of light which flows in the sky. For this very reason, it was named as the Milky Way.
Question 3.
Describe the composition and characteristics of tail stars (comets).
Answer:
Tail stars are composed of ice, dust particles, small rocks and gaseous elements.
Following are their characteristics
- Their velocity is very high.
- They revolve around the sun in a fixed elliptical orbit.
- The head of comet always faces the sun and the tail points in opposite direction.
- Sometime, they come near to the sun, and sometime, they move away from it significantly.
Question 4.
How is northern direction identified with the help of the Pole Star?
Answer:
According to Indian belief, since ancient times itself, the Pole Star has helped in identifying the northern direction. The location of the Pole Star is fixed. In order to identify its location, the first two stars of the ‘Saptarishi Mandal’ are joined by an imaginary line which, after its extenuation, joins the Pole Star on the North Pole. This can be understood with the help of the given diagram.
Long Answer Type Questions
Question 1.
Describe in brief the conventional story popular in context to the Dhruv Tara.
Answer:
A child named Dhruv was the son of king Uttanpaad and queen Suniti. The king had one more son named Uttam, who was born from his second queen Suruchi. The king liked Suruchi more. One day, the king was playing with his son Uttam in his lap. Dhruv came and wanted to play in his father’s lap. But queen Suruchi did not like this and asked Dhruv to go to Lord Vishnu and receive his blessings to become her son so as to get the right to sit in the king’s lap.
Insulted Dhruv became determined and he kept on praying to Lord Vishnu for six continuous months. God became happy at the child’s meditation and blessed him that he would become a great and intelligent king even after his death. He would become immortal as the ‘Dhruv Tara’.
Question 2.
What do you understand by the term ‘Comet’? Describe along with a diagram.
Answer:
Comets are stars with a unique shape and they are not always visible, but they can be seen for some times. Due to the gaseous composition present in them, they form a tail-like structure. These revolve round the sun in a fixed elliptical orbit. Sometimes, they come quite near to the sun and sometimes they move significantly far away from the sun. This situation arises at a fixed time and then they are clearly visible.
For example – the Hailey’s comet which appears after every 76 years. This comet has been depicted in the diagram.
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