What a star's light shows: spectra and color

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. Read this first

   Three spectrum strips labeled A to C

   Smooth rainbow; bright lines on black; dark lines on a rainbow.

2. 1.

   A hot, dense glowing object, such as a lamp filament, gives which kind of spectrum, by Ari's reading?

   • A smooth rainbow with no lines
   • No light
   • Bright lines on a dark background
   • Dark lines crossing a rainbow
3. 2.

   A hot, thin gas glowing in a tube gives which kind of spectrum, by Bo's reading?

   • Dark lines crossing a rainbow
   • One color, with no lines
   • Bright lines on a dark background
   • A smooth rainbow
4. 3.

   Starlight passes through the star's cooler outer gas. Which kind of spectrum reaches Kira's telescope?

   • Bright lines on black
   • A smooth rainbow, since the gas is see-through
   • Pure black
   • A rainbow crossed by dark lines

5. Table, Lab lines (NIST, air wavelengths), with columns Element, Lines (nm)

   Hydrogen, 656.3, 486.1, 434.0, 410.2; helium, 587.6; sodium, 589.0, 589.6; calcium, 393.4, 396.8.

6. 4.

   A star's dark lines sit at 656.3, 486.1, 434.0 and 410.2 nm. Which element matches, by Jun's reading?

   • Sodium
   • Hydrogen
   • Helium
   • Calcium
7. 5.

   A star shows dark lines at 393.4 and 396.8 nm. Which element matches, by Milo's reading?

   • Sodium
   • Calcium
   • Helium
   • Hydrogen, since 410.2 is close
8. 6.

   Four star dots colored red, yellow, white and blue. Which star has the hottest surface, by Noah's reading?

   • The red star
   • The yellow star, like the Sun
   • The white star, since white is brightest
   • The blue star
9. 7.

   One peaking at a shorter wavelength, one at a longer wavelength. As a star gets hotter, what happens to the wavelength where its light peaks, by Pia's reading?

   • It gets longer, shifting toward the red end
   • It stays the same
   • It gets shorter, toward blue
   • The peak disappears
10. 8.

    Two light curves: A peaking at 400 nm, B at 900 nm. Star A's light peaks at 400 nm (violet-blue); star B's peaks at 900 nm (infrared). Which is hotter, by Ren's reading?

    • They are equally hot
    • Star B, peaking at 900 nm
    • Star B, since redder light is hotter
    • Star A, peaking at 400 nm
11. 9.

    A star's spectrum has dark sodium lines. What does that tell Tala?

    • Sodium in the star's outer gas absorbs those wavelengths
    • Sodium is giving off extra light there
    • The star has no sodium
    • The telescope lens is dirty
12. 10.

    Bright lines on black, dark lines on a rainbow. An element's dark lines and its bright lines appear where, compared with each other, by Esme's reading?

    • Dark lines sit where the element is missing
    • At random wavelengths
    • At opposite ends of the spectrum
    • At the same wavelengths