Question

question 10
star color is determined by:

• the stars temperature.
• its luminosity.
• their distance from earth.
• their distance from the sun.

question 11
which of these star lifecycles is in order:

• ...red giant, white dwarf, black dwarf, supernova, neutron star, black hole.
• nebula, dust cloud, globule, neutron star, red giant...
• nebula, dust cloud, red giant, globule, black hole.
• ...main sequence star, red giant, neutron star, black dwarf, supernova...

question 12
nothing, not even light, can escape through the event horizon from the black hole.

• true
• false

Explanation:

Analyze star color factors

The color of a star is directly related to its surface temperature, a relationship described by Wien's displacement law in physics. Hotter stars emit more light at shorter wavelengths (appearing blue or white), while cooler stars emit more light at longer wavelengths (appearing red). Luminosity and distance affect how bright a star appears to us, but not its intrinsic color.

Evaluate stellar lifecycles

Let's analyze the proposed sequences of stellar evolution:

• Option 1: "...Red Giant, White Dwarf, Black Dwarf, Supernova, Neutron Star, Black Hole." This sequence correctly groups the lifecycle of a low-to-medium mass star (Red Giant $

ightarrow$ White Dwarf $
ightarrow$ Black Dwarf) followed by the lifecycle of a high-mass star (Supernova $
ightarrow$ Neutron Star or Black Hole).

• Option 2: "Nebula, Dust Cloud, Globule, Neutron Star, Red Giant..." is out of order because a neutron star is a late-stage remnant, whereas a red giant is an earlier phase.
• Option 3: "Nebula, Dust Cloud, Red Giant, Globule, Black Hole" is out of order because globules are early star-forming regions (protostellar stages) which must precede the red giant phase.
• Option 4: "...Main Sequence Star, Red Giant, Neutron Star, Black Dwarf, Supernova..." is out of order because a supernova must occur before a neutron star is formed, and a black dwarf is a remnant of a low-mass star, not part of the high-mass supernova pathway.

Therefore, the first option represents the correct evolutionary stages in chronological order for low-mass and high-mass pathways respectively.

Define event horizon properties

By definition in general relativity, a black hole is a region of spacetime where gravity is so strong that nothing—no particles or even electromagnetic radiation such as light—has enough energy to escape from it. The boundary of this region is called the event horizon. Therefore, the statement is true.

Answer:

Question 10

• (A) the stars temperature. (Correct answer)
• (B) it's luminosity.
• (C) their distance from Earth.
• (D) their distance from the Sun.

Question 11

• (A) ...Red Giant, White Dwarf, Black Dwarf, Supernova, Neutron Star, Black Hole. (Correct answer)
• (B) Nebula, Dust Cloud, Globule, Neutron Star, Red Giant...
• (C) Nebula, Dust Cloud, Red Giant, Globule, Black Hole.
• (D) ...Main Sequence Star, Red Giant, Neutron Star, Black Dwarf, Supernova...

Question 12

• (A) True (Correct answer)
• (B) False