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:
22
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:
23
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:
24
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:
25
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:
26
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:
27
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.
Ques:
28
Time taken by the Sun to revolve around the centre of our galaxy is –
Correct Answer:
(C)
25 crores years
Sun is one of the stars of our galaxy (Milky Way). Every star of the galaxy revolves around the galactic centre and the time taken by a star in revolving around this centre depends upon the distance between the galactic centre and the star. Sun is relatively far from the centre, so it takes more time to revolve around. Sun is at a 7.94 KPC or 25.896 thousand light years away from the centre and with a speed of 220 Km/sec, it takes 22.5 to 25 crore years, to revolve around the centre of the Milky Way galaxy. This period is called ‘Cosmic Year or Galactic Year’.
Ques:
29
Who first propounded that the Sun is the centre of our Solar system and the earth revolves around it?
Correct Answer:
(D)
Copernicus
Nicolaus Copernicus was an astronomer, scientist, mathematician of Poland. In 1514, Copernicus propounded the Heliocentric Theory of the solar system in his work 'Commentariolus' (Little commentary). Notably, Indian astronomers Varahamihira propounded the same theory around a thousand years before Copernicus in the sixth century. He mentioned that the moon revolves around the earth and the earth rotate around the sun.
Ques:
30
Sun's halo is produced by the refraction of light in –
Correct Answer:
(C)
Ice crystals in Cirrus clouds
The Sun’s halo is a circle which appears around the sun. Whenever Sun rays pass through the ice crystal present at the upper level of cirrus clouds, sun's halo becomes visible due to the refraction of rays.