profc.jpg (13600 bytes)Use these questions to test your understanding. If you get them wrong, you will be linked back to the relevant part of the notes. 
Be sure you study them thoroughly (don't just get a quick fix for your mistake) so your overall understanding is improved.

 

 

 

 

 

 

1. The best place to look for stars just beginning to form is

a. in empty space             b. in a molecular cloud

c. in a reflection nebula              d. in a supernova remnant

e. near the Sun

 

2. The gas in an HI region is comprised of

a. hydrogen gas with electrons in the ground state                  b. ionized hydrogen gas

c. hydrogen iodide molecules                      d. x-ray emitting material

e. gas consisting of protons only

3. Which physical force dominates the process of star formation?

        a. strong nuclear             b. weak nuclear             c. electrical             d. gravitational        e. reactional

 

4. A molecular cloud is

        a. a large, cold, dense collection of interstellar gas and dust

        b. interstellar dust that is lit up by a nearby star and scatters some of the light toward us

        c. an interstellar cloud made purely of complex molecules, mostly containing carbon

        d. a region where a very hot star is ionizing the nearby gas

        e. none of the above

 

5. A newly formed massive, hot star changes the surrounding interstellar gas into

    a. a molecular cloud

    b. a glowing cloud of excited gas called an HII region

    c. a dark globule seen as a shadow against the background light

    d. an HI region

    e. interstellar dust

 

6. Interstellar dust makes the things behind it look

    a. bluer and fainter

    b. greener and brighter

    c. redder and more diffuse

    d. it blots them out completely

    e. redder and fainter

 

7. Disks form around young stars

    a. if the cloud from which the star forms is too massive for all of it to fall into the star

    b. when the new star passes through a dense cloud and it is attracted to the star

    c. from material that was spinning around the protostellar core too fast to fall into the star

    d. when a second star that formed in orbit breaks up

    e. disks are something that only form around older stars

 

8. To form a real star, an object must be massive enough to

    a. have enough gravity to hold planets in orbit

    b. make an HII region

    c. explode as a supernova

    d. create enough pressure and heat in its core for hydrogen fusion

    e. burn hydrogen and helium into heavier elements