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Page 481
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Standards-Based Assessment
TEST PRACTICE
CLASSZONE.COM
Analyzing a Chart
8.4.b, 8.4.c
Use the chart and diagram to answer the next six questions.
Classification of Stars
Hertzsprung-Russell (H-R) Diagram
Class
Color
Surface
Temperature (°C)
O
B
A
F
G
K
M
blue-white
blue-white
white
yellow-white
yellow
orange
red
above 25,000
10,000–25,000
7500–10,000
6000–7500
5000–6000
3500–5000
below 3500
1. Which class of star has the lowest surface
temperature?
a. O
b. B
c. G
d. M
2. Which class of star has the highest surface
temperature?
a. O
c. G
b. B
d. M
3. What would be the color of a star with a
surface temperature of 8000ºC?
a. blue-white
c. orange
b. white
d. red
4. Toward the end of their life cycles, very massive
stars expand in size, and their surface temperature becomes lower. Which of the following is
an example of this change?
a. A white star becomes a blue-white star.
b. A blue-white star becomes a red star.
c. A red star becomes a blue-white star.
d. A yellow star becomes a yellow-white star.
highest
1
3
Luminosity
s8pe-414st-ca
2
4
lowest
40,000
20,000
10,000
5000
2500
Surface temperature (˚C)
5. The H-R diagram above shows the surface
temperatures and luminosities, or true
brightnesses, of four stars. Which of the
stars is a type O?
a. 1
b. 2
c. 3
d. 4
6. Which two stars on the H-R diagram have the
most similar surface temperatures?
a. 1 and 2
b. 1 and 3
c. 2 and 3
d. 3 and 4
Extended Response
Answer the two questions below in detail.
7. Why is looking at a star in the night sky like seeing
back into time?
8. How could you use two flashlights to demonstrate
the concept that the apparent brightness of a star
is affected by its distance from Earth? You can
include a diagram as part of your answer.
Chapter 14: Stars, Galaxies, and the Universe 481
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