Q3 of 11 Page 134

Answer the following question.

How do stars form?

Interstellar clouds are huge clouds of dust and gas present between the stars and the galaxy. Size of interstellar clouds are about a few light years where one light year is equal to km. These interstellar clouds contract due to disturbances and due to these contraction density and temperature increases and a dense sphere of hot gases are formed.


A sufficient temperature and density nuclear energy generation starts, due to this gas sphere becomes self-luminous and a star is formed or in other words a star is born.


More from this chapter

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1

Search and you will find

(a) Our galaxy is called.........


(b) For measuring large distances........is used as a unit


(c) The speed of light is............km/s


(d) There are about..........stars in our galaxy


(e) The end stage of the Sun will be......


(f) Stars are born out of.....clouds


(g) Milky Way is a...........galaxy


(h) Stars are spheres of...........gas


(i) The masses of other stars are measured relative to the mass of the.............


(j) Light takes ................ to reach us from the Sun while it takes...........to reach us from the moon


(k) The larger the mass of a star the faster is it’s.......


(l) The number of fuels used in the life of a star depends on it’s............

 2

Who is telling lies?

(a) Light year is used to measure time


(b) End stage of a star depends on its initial mass


(c) A star ends its life as a neutron star when the pressure of its electrons balances its gravity


(d) Only light can emit from the black hole


(e) The Sun will pass through the supergiant stage during its evolution


(f) The Sun will end its life as a white dwarf

 3

Answer the following question.

Why do stars evolve?

 3

Answer the following question.

What are the three end stages of stars?