Balbharati Class 8 General Science Solutions Life Cycle of Stars
Welcome to NCTB Solutions. Here with this post we are going to help 8th class students for the Solutions of Balbharati Class 8 General Science Book Chapter 19, Life Cycle of Stars. Here students can easily find step by step solutions of all the questions in Life Cycle of Stars. Also our Expert Science Teacher’s solved all the problems with easily understandable language with proper guidance so that all the students can understand easily. Here in this post students will get chapter 19 solutions. Here all the Question Answer are based on Balbharati latest syllabus. Here all the question and answer are based on Maharashtra State Board latest syllabus.
Life Cycle of Stars Exercise question Solutions :
Question no – (1)
(a) Our galaxy is called Milky way.
(b) For measuring large distances Light year is used as a unit.
(c) The speed of light is 3,00,000 km/s.
(d) There are about 10¹¹ stars in our galaxy.
(e) The end stage of the Sun will be White dwarf.
(f) Stars are born out of Interstellar clouds.
(g) Milky way is a Spiral galaxy.
(h) Stars are spheres of Burning gas.
(i) The masses of other stars are measured relative to the mass of the Sun.
(j) Light takes 8 minutes to reach us from the Sun while it takes 1 sec to reach us from the moon.
(k) The larger the mass of a star the faster is its fuel used.
(l) The number of fuels used in the life of a star depends on its Mass.
Question no – (2)
(a) Light year is used to measure time
= This statement is False.
Because, Light year is not used to measure time it is used to measure distance.
(b) End stage of a star depends on its initial mass
= This statement is True.
(c) A star ends its life as a neutron star when the pressure of its electrons balances its gravity
= This statement is False.
Because, A star ends its life as a Neutron star when the pressure of its neutrons balances the gravity.
(d) Only light can emit from the blank hole.
This statement is False.
Because, light does not get emitted from the black hole.
(e) The Sun will end its life as a white dwarf
This statement is True.
Question no – (3)
(a) A star is formed when huge clouds of dust and gas in the space starts contracting due to some disturbance. Due to this contraction, the density and temperature starts increasing and dense sphere of hot gas is formed. Once the temperature and density reaches a sufficient level nuclear energy generation takes place. Because of this energy generation, the star becomes self luminous and in that moment a star is formed.
(b) A stars evolves when the fuel in a sun depletes which results in a temperature drop that disturbs the balance between gas pressure and gravitational force, the star begins to contract and evolve into their end form depending on their masses.
(c) The three end stages of star are –
- White dwarf
- Neutron star
- Black hole
(d) The name black hole was given because any light falling in these stars does not get reflected back but is absorbed and all that we can see is a black dot in its place.
Question no – (4)
(a) If I were the sun then my properties would be as follows :
• I have a mass of 2 × 10³⁰ kg.
• I have a radius of 695700 km.
• I have a surface temperature of 5800 K.
• My core temperature is 1.5×10⁷ K.
• I am 4.5 × 10⁹ year.
• I am made up of Hydrogen, Helium and other elements heavier than helium.
(b) White dwarfs :
A white dwarf is a very dense star that is typically the size of a planet, it is the evolved form of a star that has a mass between 8 to 25 times that of sun and which has used all of its fuel.
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