This topic explores the origin, structure, and dynamics of the Solar System. It analyzes the distribution of mass, planetary formation processes, asteroid belts, Kuiper belt objects, and cosmic forces regulating planetary orbits.
Which one of the following statements is correct with reference to our solar system?
Correct Answer:
(A) The Earth is the densest of all the planets in our solar system
The average density of Earth is highest among all the other eight planets of our Solar System. It is 5.514 gm/cm3 . The density of other planets is as follows (Unit–gm/ cm3 ) Mercury (5.42), Venus (5.24), Mars (3.93), Jupiter (1.32), Saturn (0.68) Uranus (1.27), Neptune (1.63). Thus statement (a) is correct. The largest constituent element of earth is Iron (32.07%). Oxygen (30.12%) is the second and Silicon (15.12%) is the third largest element in the composition of Earth. The sun comprises 99.8% mass of the solar system. The diameter of the sun is about 109 times the Earth's diameter.
Ques: 2
The number of the planet in the solar system is –
Correct Answer:
(C) 8
Our solar system is made up of a star—the Sun and eight planets, 146 moons, a bunch of comets, asteroids and space rocks, ice, and several dwarf planets, such as Pluto. The eight planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Mercury is closest to the Sun. Neptune is the farthest.
Increasing order of distance from the sun, as follows :
(i) Mercury (57.9 million Km.)
(ii) Venus (108.2 million Km.)
(iii) Earth (149.6 million Km.)
(iv) Mars (227.9 million Km.)
(v) Jupiter (778.6 million Km.)
(vi) Saturn (1433.5 million Km.)
(vii) Uranus (2872.5 million Km.)
(viii) Neptune (4495.1 million Km.)
Ques: 3
Which is true about planets ?
Correct Answer:
(B) Planets shine though they are non-luminous bodies
Planets are a non-luminous body but they shine because they reflect the light of the Sun. Thus option (b) is correct.
Ques: 4
Which of the following pairs is not properly matched ?
Correct Answer:
(D)
The slowest moving planet Solar System - Mars
All of the given options are true, except option (d) because the slowest moving planet of the solar system is Neptune. It takes 165 years to complete one revolution around the sun.
Ques: 5
Arrange the following in decreasing order of size and select the correct answer from the codes given below :
1. Jupiter 2. Uranus
3. Earth 4. Saturn
Code :
Correct Answer:
(C) 1, 4, 2, 3
The decreasing order of the size of given planets is as follows– Jupiter > Saturn > Uranus > Earth. Size of planets in decreasing order is as follows. Jupiter, Saturn, Uranus, Neptune, Earth, Venus, Mars, Mercury.
Ques: 6
'The term 'Goldilocks Zone' is often seen in the news in the context of
Correct Answer:
(C) Search for the Earth-like planets in outer space.
In Astronomy, the circumstellar habitual zone is also called 'Goldilocks Zone'. It refers to the habitable zone around a star where the temperature is just right- not too hot and not too cold for liquid water to exist on a planet. Earth is the only planet inhabiting life in the entire solar system. It is the only planet situated in the Goldilocks zone of the solar system.
Ques: 7
Which of the following statements are correct regarding the solar system?
Mercury is the hottest planet in the solar system
Ganymede, satellite of Saturn, is the largest satellite in the solar system
Neptune is surrounded by methane gas rings of sub-zero temperature
Phobos and Deimos are two satellites of Mars
Correct Answer:
(C) Only III and IV are correct
Venus is the hottest planet in the solar system, not Mercury. This is, because its dense atmosphere acts as a greenhouse and heats the surface to about 464ºC). Ganymede is the largest satellite in the solar system, but it is a satellite of Jupiter, not Saturn. Neptune is surrounded by methane gas rings of sub-zero temperature. Mars has two small moons : Phobos and Deimos. The moons get their names from the horses that pulled the chariot of the Greek god of war, Ares.
Ques: 8
The group of stars that indicates the direction of pole, is
Correct Answer:
(A) Saptarishi
Saptarishi is a group of stars that indicate the direction of the pole. Hence, option (a) is the correct answer.
Ques: 9
Which of the following does not belong to the solar system?
Correct Answer:
(D)
Nebula
The solar system was formed around 4.568 billion years ago. The solar system consists sun (star), cosmic dust or masses attached with each other by gravitational force, planets, dwarf Planets, natural planetoid, asteroids, comets, meteoroid and cosmic dust while Nebulae is not a part of Solar System.
Ques: 10
The milky way is classified as –
Correct Answer:
(A) Spiral Galaxy
According to the theory propounded by Georges Lemaitre, 13.8 billion years ago the total cosmic substance was in the form of dense mass which spread to form a number of galaxies. An Infinite group of these swirling galaxies are visible to us collectively in the form of Universe. Every Galaxy is estimated to contain around 100 billion stars. The galaxy in which our solar system is situated is known as ‘Milky Way’. There are various shapes of galaxies, for example elliptical, spiral, irregular etc. Spitzer space telescope in 2005, produced clear proof against the preconception about the shape of Milky Way and made it clear that the shape of our Milky Way is Barred spiral.
Ques: 11
The colour of the star indicates its –
Correct Answer:
(D)
Temperature
The colour of a star indicates it's temperature. The temperature of stars of diff erent colours is as follows –
(Colours) (Temperature range)
Blue - 50,000-28,000 K
Blue-white - 28,000-10,000 K
White - 10,000-7500 K
White Yellow - 7500-6000 K
Yellow – 6000 -4900 K
Orange - 4900-3500 K
Red - 3500-2000 K
Ques: 12
The limit beyond which stars suffer internal collapse is called :
Correct Answer:
(A) Chandrashekhar limit
Subrahmanyan Chandrasekhar was an Indian astrophysicist who described the “Chandrasekhar Limit”. This limit describes the maximum mass of a white dwarf star or the mass limit above which a star will ultimately collapse into a Neutron star or a black hole. He revealed that this mass was approximately 1.44 of the solar masses. In 1983 Chandrashekhar was awarded the Nobel Prize in Physics for his work on the evolution of stars.
Ques: 13
Consider the following statements:Statement-I : Giant stars live much longer than dwarf stars.Statement-II : Compared to dwarf stars, giant stars have a greater rate of nuclear reactions.Which one of the following is correct in respect of the above statements?
Correct Answer:
(D)
Statement-I is incorrect, but Statement-II is correct
Statement-I: This statement is incorrect. Giant stars actually have shorter lifespans compared to dwarf stars. This is because giant stars burn through their nuclear fuel much more quickly due to their greater mass and higher luminosity.
Statement-II: This statement is correct. Giant stars do have a greater rate of nuclear reactions than dwarf stars. The high mass of giant stars causes them to undergo fusion at a much faster rate, producing more energy and leading to a greater rate of nuclear reactions.
Ques: 14
A group of stars arranged in a particular shape, is called–
Correct Answer:
(B) Constellation
A constellation is a group of stars forming a recognizable pattern. It is traditionally named after its apparent form or identified with a mythological figure. Hence, option (b) is the correct answer.
Ques: 15
Consider the following Statements – A person in spacecraft situated at the mid of earth and Sun will see that –
Sky is black
Stars do not twinkle
The temperature outside the spacecraft is more than that of the earth surface.
Which of the following is true –
Correct Answer:
(B) 1 and 2
Due to the absence of atmosphere in space, the sky appears black and stars do not twinkle. Twinkling of stars is caused by the passing of light through different layers of turbulent atmosphere similarly it is due to the atmosphere that light scatters to let us see the blue sky.