Tag: life cycle of stars

Questions Related to life cycle of stars

What is a planetary nebula

physics life cycle of stars evolution and end stages of stars the stars stars

  1. a disk of gas surrounding a protostar that may form into planets

  2. what is left of the planets around a star after a low-mass star has ended its life

  3. the expanding shell of gas that is no longer gravitationally held to the remnant of a low-mass star

  4. the molecular cloud from which protostars form

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Correct Option: C
Explanation:

A ring-shaped gaseous structure formed by an expanding shell of gas round an ageing star is known as nebula

Why does a star grow larger after it exhausts its core hydrogen?

physics life cycle of stars evolution and end stages of stars the stars stars

  1. The outer layers of the star are no longer gravitationally attracted to the core.

  2. Hydrogen fusion in a shell outside the core generates enough thermal pressure to push the upper layers outward.

  3. Helium fusion in the core generates enough thermal pressure to push the upper layers outward.

  4. Helium fusion in a shell outside the core generates enough thermal pressure to push the upper layers outward.

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Correct Option: A,C

Compared to the star it evolved from, a white dwarf is 

physics life cycle of stars evolution and end stages of stars the stars stars

  1. hotter and brighter.

  2. hotter and dimmer.

  3. cooler and brighter.

  4. cooler and dimmer.

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Correct Option: B
Explanation:

A star's temperature is only 5,800 K, while a white dwarf has a temperature of 100,000 K. A white dwarf's faint luminosity comes from the emission of stored thermal energy; no fusion takes place in a white dwarf wherein mass is converted to energy. Hence it is dimmer than star

What happens to the core of a star after a planetary nebula occurs? 

physics life cycle of stars evolution and end stages of stars the stars stars

  1. It contracts from a protostar to a main-sequence star.

  2. It breaks apart in a violent explosion.

  3. It becomes a white dwarf.

  4. It becomes a neutron star.

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Correct Option: C

During which of the following phases does the core of a massive star have so much gravity that even light can't escape?

physics life cycle of stars evolution and end stages of stars the stars stars

  1. Neutron Star

  2. Supernova

  3. White Dwarf

  4. Black Hole

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Correct Option: D
Explanation:

Once a black hole has formed, it can continue to grow by absorbing mass from its surroundings. The gravitational force becomes so intense that even light cannot escape from it

Why do massive stars have shorter lifespans than average stars?

physics life cycle of stars evolution and end stages of stars the stars stars

  1. They are excited to get through their lifecycles faster

  2. They have less steps in their lifecycles

  3. They burn their fuel faster

  4. They have less fuel to burn

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Correct Option: C
Explanation:

Massive stars live shorter lives than the common small stars because even though they have a larger amount of hydrogen for nuclear reactions, their rate of consuming their fuel is very much greater.

Which of the following lists contains ONLY heavy elements

physics life cycle of stars evolution and end stages of stars the stars stars

  1. Oxygen, Carbon, Iron

  2. Helium, Oxygen, Carbon

  3. Hydrogen, Helium, Carbon

  4. Iron, Hydrogen, Oxygen

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Correct Option: A
Explanation:

Helium and hydrogen being lighter gases are seen in other options other than option a. Thus , such options are incorrect options

In which of the following stages will our Sun form heavy elements?

physics life cycle of stars evolution and end stages of stars the stars stars

  1. Red giant

  2. Stellar Nebula

  3. Blackhole

  4. Main sequence

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Correct Option: A
Explanation:

 In approximately 5 billion years, the sun will begin the helium-burning process, turning into a red giant star. In a red giant, helium nuclei fuse to make carbon, followed by heavier elements such as nitrogen and oxygen.

After a supernova explosion, the remains of the stellar core 

physics life cycle of stars evolution and end stages of stars the stars stars

  1. will always be a neutron star.

  2. will be either a neutron star or a black hole.

  3. will always be a black hole.

  4. may be either a white dwarf, neutron star, or black hole

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Correct Option: B

Analyzing the spectra of stars, the hottest stars are

physics life cycle of stars evolution and end stages of stars the stars stars

  1. red

  2. orange

  3. bluish white

  4. there is no correlation between color and temperature

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Correct Option: C
Explanation:

The temperature of the stars are related to their colors by weins displacement law. Larger the temperature, smaller is their wavelength. Thus, of the colors given , red has maximum wavelength and hence smaller temperature, while bluish white has lesser wavelength and highest temperature. Thus, the star that emits bluish-white color has maximum temperature