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Online Quiz



1

The Sun’s evolution from youngest to oldest stage is:
A)white dwarf, red giant, main-sequence, protostar
B)red giant, main-sequence, white dwarf, protostar
C)protostar, red giant, main-sequence, white dwarf
D)protostar, main-sequence, red giant, white dwarf
2

Protostars initially do not experience hydrogen fusion. How then do they heat up?
A)The light from nearby stars.
B)Gravitational energy from infalling material.
C)Fusion of hydrogen into helium.
D)Energy from their magnetic fields.
3

Because protostars are at a low temperature (for a star!) and surrounded by dust and gas, astronomers must observe them with
A)radar.
B)ultraviolet telescopes.
C)infrared and radio telescopes.
D)gamma ray telescopes.
4

What is a T Tauri star?
A)Any variable star.
B)A red giant with a peculiar spectrum.
C)Any star found in the constellation of Taurus.
D)A young star that exhibits variable light and outflowing gas.
5

A star enters the main sequence when
A)nuclear fuel in its core can supply enough energy to stop its collapse.
B)it collapses, and its envelope becomes degenerate.
C)it stops fusing nuclear fuel in its core and starts to expand.
D)it forms planets.
6

What determines how long a star stays on the main sequence?
A)Its temperature and mass.
B)Its luminosity and radius.
C)Its mass and luminosity.
D)Its radius and mass.
7

A star leaves the main sequence when
A)nuclear fuel in its core can supply enough energy to stop its collapse.
B)it collapses, and its envelope becomes degenerate.
C)it stops fusing hydrogen in its core and starts to expand.
D)it forms planets.
8

When a star like the sun evolves into a red giant, its core
A)expands and cools.
B)contracts and heats.
C)expands and heats.
D)contracts and cools.
9

Why can high-mass stars “burn” helium more easily than low-mass stars?
A)A high-mass star's core is already very hot, so it only needs to compress its core a little to burn helium.
B)High-mass stars are already burning helium on the main sequence.
C)Low-mass stars have proportionately less helium than high-mass stars.
D)This statement is false. It is much harder for high-mass stars to burn helium.
10

What is a “pulsating star”?
A)A rotating neutron star that emits radio waves in a narrow beam.
B)A star whose luminosity changes as it swells and shrinks rhythmically.
C)A planetary nebula.
D)A star whose mass changes as it comes into contact with another star.
11

What is a “planetary nebula”?
A)It is the disk of gas around a young star.
B)It is the cloud from which protostars form
C)It is a shell of gas ejected from a star late in its life.
D)It is what is left when a white dwarf star explodes as a supernova.
12

What is left when a planetary nebula dissipates?
A)A red giant
B)A black hole.
C)A white dwarf.
D)A neutron star.
13

Low-mass stars like the Sun probably do not form iron cores during their evolution because
A)all the iron is ejected when they become planetary nebulas.
B)their cores never get hot enough for them to make iron by nucleosynthesis.
C)the iron they make by nucleosynthesis is all fused into uranium.
D)their strong magnetic fields keep their iron in their atmospheres.
14

What makes a high-mass star's core collapse?
A)Energy from its outer layers compresses its core.
B)The only thing that can make a star's core collapse is a collision with another star.
C)Massive stars develop iron cores that cannot fuse anymore, so the core collapses under gravity.
D)Massive stars' cores don't collapse. They expand and become planetary nebulas.
15

What can be observed from Earth when a supernova explodes?
A)Light and neutrinos.
B)Electrons and geraniums.
C)Photons and neutrons.
D)Phasers and betazoids.







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