RBSE Class 9 Science Chapter 12 Celestial Bodies and Indian Calendar Solutions is the most effective resource that helps students to get a strong grip on the entire concepts of the chapter. Students who solve these solutions for practice find it easy to revise the complete chapter thoroughly. They can solve these solutions and master the subject most efficiently. Practising these questions from the RBSE Class 9 Solutions for Chapter 12 Science enable students to comprehend all the major topics from the chapter. Students are advised to solve these chapter wise important questions from the RBSE Class 9 Science in order to prepare most competently for the Class 9 exams. Meanwhile, students are also encouraged to implement the strategic learning process so that they can boost their performance. Here, we have listed the important questions from Chapter 12, Celestial Bodies and Indian Calendar of RBSE Class 9 Science Textbook. Answering these questions helps the students to score high marks. Students will also be able to get a proper foundation of the subject before moving on to higher classes, thus helping them to do well for the academic year.
Rajasthan Board Class 9 Science Chapter 12- BYJU’S Important Questions & Answers
RBSE Class 9 Science Chapter 12 Objective Questions-Important Questions and Solutions
1. The celestial bodies having their own light and heat are known as :
Answer: (a) Stars
2. In which category has the moon been placed in the solar system ?
Answer: (c) Satellite
3. The number of nakshatra according to panchang is :
Answer: (b) 27
4. What is the number of rashis according to the Panchang?
Answer: (c) 12
5. Which is the largest body of our solar system:
Answer: (b) Sun
6. Which is the largest planet of our solar-system :
Answer: (a) Jupiter
7. The “adik mass” (extra month) appears in the lunar calendar at an interval of :
(a) 1 year
(b) 2 years
(c) 3 years
(d) 4 years
Answer: (b) 2 years
8. At the initiation of the southern movement the earth is in which rashi:
Answer: (a) Cancer
1. Who was the author of the book Lilawati based on arithmetic?
Answer: Bhaskaracharya is the author of the book Lilawati based on Arithmetic.
2. The first Bhartiya satellite has been named after, which great scientist?
Answer: The first Bhartiya satellite was named as “Aryabhata”, to commemorate his work.
3. Which tithi falls after Chaturdashi of the brighter phase (Shukl paksha)?
Answer: After Chaturdashi of the brighter phase (Shukl Paksha), it is the paurnami or poornima.
4. What will be the name of the lunar month if the moon on Purnima is in Mrigshira Nakshtra?
Answer: The name of the lunar month if the moon on Purnima is in Mrigshira Nakshtra is the Margashirsha.
5. Which planet has the smallest period of revolution?
Answer: Mercury has the smallest period of revolutions for 88 days.
6. Write the name of the planets according to their increasing distance from the sun.
Answer: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune are the names of the planets, according to their increasing distance from the sun.
7. Name the terrestrial planets.
Answer: Mercury, Venus, Earth and Mars are called terrestrial planets as they have a ground.
8. Apart from earth, which planet has the possibility of existence of life?
Answer: Recent discoveries have indicated the presence of life on Mars. Hence, apart from Earth, Mars is the planet with the possibility of existence of life.
9. According to the Bhartiya Panchang, which ‘grah’ belongs to the category of shadow planets?
Answer: According to the Bhartiya Panchang, both Rahu and Ketu belong to the category of shadow planets.
10. Two planets A and B are at a distance of X and Y, from the sun, respectively. If the value of Y is more than X, then which planet will have a longer revolutionary period.
Answer: The greater the distance of the planet from the sun, then more is its time of revolution in its orbit. Hence, if y is at a greater distance from than X from the sun, then Y will have a greater revolutionary period.
1. Write the names of planets with increasing distance from the earth?
Answer: Venus, Mars, Mercury, Jupiter, Saturn, Uranus and Neptune are the names of the planets with increasing distance from the earth.
2. Write the name of the five parts of the Bhartiya Panchang.
Answer: The five parts of the Bharatiya Panchang includes Karana, Nakshtra, Yog, Tithi and Var .
3. What is meant by Nakshtra? How many nakshatras are there? Name any five nakshatra.
Answer: Nakshtra (Constellations/asterisms) : The path of revolution of moon about the earth has been divided into 27 sectors. A nakshtra is a sector along the lunar ecliptic. According to hindu astrology there are 27 Nakshtras’ or sectors along the ecliptic. Ashwini, Rohini, Kritika, Bharni, Mrigashira and so on are the names of the Nakshtra.
4. How is a tithi determined according to the Bhartiya Panchang? Explain in brief.
Answer: Similar to the date of the english months, Tithi is related to the lunar month with two phases in a lunar month that are known as the ‘Shukl paksha’ and the ‘Krishan Paksha’. There are 15 ‘tithis’ in each ‘Paksha’, two of them are the Full Moon (Poornima) and the New Moon (Amavasya). The tithis pratipada takes place when the angle is 0-12º. Thus, other thiti also occur for each consecutive 12º longitude.
5. Write the names of the planets according to their increasing size.
Answer: Names of the planets as per their increasing size are as follows:
6. What is meant by northern and southern movement?
Answer: The earth’s orbit is divided into two parts of six months each.The six months that the northern hemisphere is tilted towards the sun and receives the direct sun rays is the northern movement (Uttarayan). The next six months the tilt of the northern hemisphere is away from the sun and the position of the sun is east -south west. This is the Dakshirayan or the southern movement.
7. Explain the various motions of the earth.
Answer: The movement of the earth around the sun is called a revolution and the earth completes its one revolution around the sun in a year (12 months). During its revolution around the sun, when Mercury comes in between the Sun and the Earth, it appears as a dark spot on the sun’s face which gradually moves ahead. This is known as the Mercury Transit. Similarly Venus transit also takes place. Meanwhile, the motion of the earth around its own axis is known as rotation. Learn more about Rotation and Revolution.
8. According to the Bhartiya Panchang, rashi are related to whose movement? How are the rashis determined?
Answer: In the same way that nakshtra’s have been named on the basis of the path of the moon, rashi are related with earth’s movements. The earth’s orbit has been divided into 12 sectors and each sector is considered to be a rashi. As per the Bharatiya Panchang, the names of these rashis and their shape are determined on the basis of various constellations present in the sky. Since earth takes nearly 12 months to orbit around the sun, the sun will remain in each rashi for about a month. The position of these rashis is known as the twelve solar months. The earth’s orbit has been divided into 12 parts. The constellations (nakshtra) present in each part of the orbit are known as the Rashi. They are – Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius and Pisces.
9. What is the meaning of Makar-Sankranti?
Answer: Sankranti occurs when the earth moves from one rashi to another. It is also known as the sun’s transition. When the sun transits in Capricorn it is known as Makar sankranti. Makar Sankranti mostly falls on 14 January.
10. What do you understand by “adhik maas”?
Answer: Adhik maas takes place every three years, when there is an increase in lunar month to coordinate between the lunar and solar months. One month is decreased every 150-200 years.
11. Explain mercury transit. Compare it with the Venus transit.
Answer: Mercury transit and venus transit are predictable celestial events. Mercury transit is when during its revolution around the sun, mercury comes in between the Sun and the Earth forming a dark spot on the sun’s face that gradually moves ahead. Similarly, during Venus transit, transit of the venus occurs when venus comes in between the earth.
1. Write the main points of the biography of Aryabhata and explain his contributions in
Answer: A great astronomer and mathematician of ancient Bharat, Aryabhatt was born in 476 bc. He produced 108 verses and 13 added verses in the introduction, which have been divided into 4 chapters. Geetikpaad of 13 verses describes the bigger units of time like – Kalp, Manvantar, Yug etc.Ganitpaad of 33 verses is a collection of geometric progression and simple, quadratic , simultaneous and indeterminate equations. Meanwhile, Kaal Kriyapaad of 25 verses
are the different units of time and the method of determining the position of planets on a particular day. It also covers the calculation of “adhika mass” (i.e. the extra lunar month) and “Kshya mass’ (i.e. the decay month or the decrease in lunar month) and the names of the various days of a week. Finally, Golapada of 50 verses included the geometric and trigonometric aspects, orbits, shape of the earth, reasons of day and night etc. At the same time, there are also other discoveries that Aryabhatt was famous for:
- Represent accurately the value of π
- Discovery that earth rotates on its own axis
- Find out the relation between the circumference and radius of a triangle
- Determine the area of a triangle
- Presented a hypothesis regarding the geocentric model of the solar system and analyzed the reasons for the solar and lunar eclipse.
- The time taken by earth to rotate around fixed stars was calculated to be 365 days 6 hours 12 minutes 30 seconds – which by the present day calculations have an error of just 3 minutes 20 seconds
- Calculated the perimeter of the earth which was just 0.2% less than the actual value.
- The first person to create the sine tables from 0 to 90º.
2. Outline the biography of Bhaskaracharya and describe in detail the work accomplished by him.
Answer: Bhaskaracharya or Bhaskar II, born in 1114 AD at Bijapur, Karnataka was the famous mathematician and astronomer of the 12th century in Bharat. He made systematic use of the decimal number system. Bhaskaracharya is also known for his commentaries on the work of Aryabhatta. He also produced his own works based on these texts. At the age of 36 years, he also published a book in Sanskrit called Siddhant Shiromani, which consists of four parts-Lilawati, Bijaganitadhyay, Grahganitadhyay and Goladhyay. These give a detailed description of Arithmetic, Algebra, Planetary Mathematics and Sphere. He had also assumed the role as the chief of Ujjain’s Astronomical observatories. In one of his books, there was a mention that the earth pulls celestial bodies towards itself by virtue of a special force. Another renowned work of his is ‘Karan Kautuhal. He is also known for some astronomical calculations that are considered while preparing the Panchang or almanac. His other text is Surya Siddhanta, which makes clear that the earth is round and moves around the Sun continuously in a defined orbit.
3. What is the basis of the nomenclature of the Bharatiya months (maas)? Write the names of the Bhartiya months (lunar months) and explain in detail the celestial position formed at that time in the sky.
Answer: The lunar months governed by the movement of the moon cover 12 lunar months that have been named as per the constellations and rashis in the path of the moon’s orbit. The Lunar Month is named as per the position of the moon on full moon day in a given nakshatra. The 12 lunar months, according to the Bharatiya Panchang are Chaitra, Vaishakha, Jaishtha, Aashad, Shravan, Bhadrapada, Ashwini, Kartika, Margshirsh, Paush, Magh and Phalgun. There are two phases in each month (Maas) Shukla paksha (increasing phase) and Krishan paksha (decreasing phase). Each paksh has 15 tithis. The last tithi of sukla paksha is Poornima, while that of krishan paksha is Amavasya. After amavasya, when the moon appears in Aries rashi and Ashwini Nakshtra and gradually increase phase by phase becoming the full moon in Chitra Nakshtra, then this month is called the “Chaitra” (because of Chitra Nakshtra). In other words, the month is named according to the position of the moon, on Full Moon day, in a particular nakshtra. Like the full moon will be in Kritika Nakshtra during the Kartik month.
|S.No.||Nakshatra||Rashi||Name of the Month|
4. Write in detail about our solar system.
Answer: The solar family consists of the celestial bodies that are orbiting in elliptical paths around the sun. The solar system includes planets, satellites, meteorites, comets, asteroids and many unknown bodies that are revolving around the sun because of its gravitational force. Bodies that are revolving around the sun are planets, while the bodies revolving the planets are the satellites. For example, the Earth revolving around the sun is a planet, while the moon revolving the earth is a satellite. The planets do not have their light and heat and are reflecting the light of the sun and other planets. Sun is the biggest body of our solar system with its mass making up over 99% of the mass of our solar system. Sun is a large ball about 10 lakh times bigger than our earth and made up of gases like hydrogen and helium. It is a powerful source of energy and only a small part of the energy emitted by the sun reaches the earth surface. Sun is the cause of rains on the earth, occurrence of day and night and change of seasons. This solar energy also affects the life cycle of all the planets and animals. There are about 8 celestial bodies categorised as planets in the solar system. However, as per the Bhartiya Panchang, there are 9 planets. Planets : Mercury, Venus, Earth and Mars are known as the terrestrial planets because they have a ground while the next four Jupiter, Saturn, Uranus and Neptune are heavy planets made up of gases. Then there are Pluto, Aries, Ceres etc, termed the Dwarf planets. There are also smaller solar system bodies consisting of 166 known satellites and astronomical bodies such as the asteroid belt, comets, meteorites and the dust present in between the planets. The dust and gaseous bodies revolving in space are also pulled towards the earth as a result of its gravitational force. When they enter the earth’s atmosphere they shine bright as a result of their friction in the atmosphere and most of them are burnt down to ash before reaching the earth’s surface. They are known as meteor. Those bodies that do not burn away completely and fall on the earth in the form of rocks, are termed as meteorites. Mercury does not have any atmosphere and it is nearest to the sun. Nights are very old and the days are hot on the planet. In the meantime, there are clouds of sulphuric acid in the atmosphere of Venus. The ground surface is filled with rocks and volcanoes. Venus is the brightest planet and in common parlance is called the evening star and morning star. It is also known as earth’s sister as its size and mass are equal to that of earth. Also, since the Earth rotates from west to east, we can see the sunrise in the east and the sun-set in the west. Venus and Uranus rotate from east to west.
Mars, also known as the ‘Red Planet’ has highest mountain “Nix Olympia,” which is three
times higher than Mount Everest. Recent discoveries have indicated the presence of life on
this planet. Phobos and Deimos are the satellites revolving around mars. Finally, Jupiter, the largest planet of our solar family, has a red spot that is actually a large hurricane situated in the disturbed clouds. Of the 16 satellites of this planet the important ones are Ganymede, Io, Europa, Callisto and so on. The famous ring around the saturn, in the meantime is made up of thousands of spiral belts of waves. Surrounding it there is a ring of gas and minute rock
debris. Its famous satellites are Phoebe, Tethys and Mimas. Now, the planets as per the Panchang are also given here. They are Sun, Moon, Mars, Mercury, Venus, Jupiter, Saturn, Rahu and Ketu.
RBSE Class 9 Science Chapter 12 Additional Questions-Important Questions and Solutions
1. How can you observe celestial bodies that are invisible to the naked eye?
Answer: You can use a telescope to view celestial bodies that are invisible to the naked eye.
2. What is an almanac?
Answer: The Indian calendar or almanac is an astronomical book created on the basis of mathematical calculations that determine the names of various celestial bodies and their movements. Seeing, as how millions of ages ago there were no watches or any type of time measuring devices, our ancestors determined time, date, month etc. by observing the
position of these celestial bodies. The Indian almanac was prepared on this basis.
3. What is a Vaar?
Answer: Considered as one among the five main parts of the Bharatiya Panchang, Vaar is the same as the days of the week and there are seven days.
4. The celestial bodies present in the solar system have been categorized into three categories according to the approval of the International astronomical union conference, Prague. What are they?
Answer: The celestial bodies of the solar system are divided into three categories that are planets, dwarf planets and small solar system bodies.
5. On 24 September 2014 the Bhartiya scientists were successful in establishing our space shuttle in the orbit of Mars. Where was it launched from?
Answer: On 24 September 2014, Bharatiya Scientists successfully attempted a maiden launch of a Mars space ship from SriHarikota, Andhra Pradesh at a very low cost.
6. Name the six signs that fall in the path of the earth during northern movement?
Answer: The six signs that fall in the path of the earth during the northern movement includes the Capricorn, Aquarius, Pisces, Aries, Taurus and Gemini.
7. What is Summer Solstice and Winter Solstice?
Answer: On 21st June, when the Tropic of Cancer receives direct rays of the sun it is called summer solstice. While, on 22nd December, the Tropic of Capricorn receives direct rays of the sun for winter solstice.
8. When is the length of the day and night equal?
Answer: When the Equator receives direct rays of the sun with neither of the two poles tilted
towards the sun, the length of the day and night is equal to 12 hours each. This happens
twice a year – on 21st March that is Spring Equinox and on 22nd September, for Autumn Equinox.
9. Who was Varahmihir?
Answer: Varahmihir, a Bhartiya mathematician and astronomer of the 5th-6th century was born in a Brahmin family at Ujjain in 499 AD. He learnt the traditional mathematics and astronomy from his father Adityadas and carried extensive research in the field. The center of advanced mathematical science that was developed by him at Patthak (Ujjain) remained unique for 700 years.
10. Which of the five astronomical texts do the panchasiddhantika summarize?
Answer: The five astronomical texts summarized in Panchasiddhantika are Surya Siddhanta, Romak Sidhhanta, Paulisa Siddhanta, Vasishtha Siddhanta and Paitama Siddhanta.
11. Name the other Bharatiya mathematicians who have done commendable work.
Answer: Bhartiya mathematicians who have done commendable work includes Brahmguta (628
AD), Jain mathematician Mahaveeracharya (80 AD), Shri Bhaskaracharya (991 AD) Ramanujan
(1887) Subhramanyan Chandrashekhar (1936) and Sawai Jai Singh II (1686-1743 AD) of the Jaipur Royal family.
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