Tag: physics

Questions Related to physics

Radiation pressure on any surface :

electromagnetic spectrum electromagnetic waves physics

  1. is dependent on wavelength of the light used

  2. is dependent on nature of surface and intensity of light used

  3. is dependent on frequency and nature of surface

  4. depends on the nature of source from which light is coming and on nature of surface on which it is falling.

Show answer
Correct Option: B
Explanation:

Radiation pressure is given by   $P _R = \dfrac{(1+\alpha) I}{c}$
where $\alpha$ is the coefficient of reflection of the surface.
For completely reflecting surface  $\alpha =1$
For completely absorbing surface  $\alpha = 0$
So,  radiation pressure depends on the nature of surface on which the light is falling but independent of wavelength of light falling.

What type of star is our Sun? 

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

  1. low-mass star

  2. intermediate-mass star

  3. high-mass star

  4. blackhole

Show answer
Correct Option: A
Explanation:

Stars are sequence can range from a tenth of the mass of the sun to up to $200$ times as massive.

Sun is a low mass star.

What do astronomers mean when they say that we are all "star stuff"? 

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

  1. that life would be impossible without energy from the Sun

  2. that life would be possible without energy from the Sun

  3. that the carbon, oxygen, and many elements essential to life were created by nucleosynthesis in stellar cores

  4. None of these

Show answer
Correct Option: C

The brightness of a star which can be seen from earth is called

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

  1. absolute magnitude

  2. apparent magnitude

  3. light year

  4. parallax

Show answer
Correct Option: B

What is the first stage of a stars life.

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

  1. Nebula collapsing under itself

  2. Supernova of old star

  3. Planets collapsing

  4. Fusion of atoms

Show answer
Correct Option: A
Explanation:

A star is a luminous globe of gas producing its own heat and light by nuclear reactions (nuclear fusion). They are born from the nebula and consist mostly of hydrogen and helium gas. Surface temperatures range from 2000 C to above 30,000 C, and the corresponding colors from red to blue-white. 

All stars are born in what phase of their lifecycle?

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

  1. Supernova

  2. Red giant

  3. main sequence

  4. stellar nebula

Show answer
Correct Option: D
Explanation:

Nebulae are the collection of massive clouds of dust, hydrogen and helium gas, and plasma. These form the origin of the birth of a star.

What happens during the Main Sequence phase of a star?

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

  1. Hydrogen atoms are fused into helium atoms

  2. The star explodes and releases energy

  3. Helium atoms are fused into heavy elements

  4. The star is born out of dust and gas

Show answer
Correct Option: A
Explanation:

Main sequence stars fuse hydrogen atoms to form helium atoms in their cores. About 90 percent of the stars in the universe, including the sun, are main sequence stars. 

A main sequence star is 

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

  1. A star that shines steadily due to nuclear fusion

  2. Several stars close together

  3. A star with planets orbiting it

  4. A Nebula that skips a protostar and is instantly turns into a star.

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Correct Option: A

What is a Star?

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

  1. A cloud of particles held together loosely by their own collective gravity

  2. A very big collection of matter, mostly gas compressed to incredible pressure and heat by gravity.

  3. A nuclear explosion caused by a growth of hydrogen onto the surface of a white dwarf star

  4. A ball of gas.

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Correct Option: B

What is the name of the process that forms heavy elements from atoms like helium?

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

  1. Nuclear Fission

  2. Attraction

  3. Conjugation

  4. Nuclear Fusion

Show answer
Correct Option: A
Explanation:

Smaller elements fuse together to form massive elements. this process is known as nuclear fusion