Passage VI
A star's brightness is described by its magnitude. As magnitude increases, brightness decreases. A star's apparent magnitude is measured from Earth. A star's absolute magnitude is the magnitude that would be measured 10 parsecs from the star (1 parsec [pc] = 3.1 x 1016 m). V represents the apparent magnitude of a star's visible light. MV and MB represent the absolute magnitudes of a star's visible light and blue light, respectively.
Table 1 lists V, MV, V - MV, and MB - MV for particular stars in each of 4 hypothetical star clusters (SCs). Figure 1 shows SC age versus MB - MV. Figure 2 shows SC distance from Earth versus V- MV. Table 2 lists a star's power output of visible light for a given MV.
30. Based on Figure 1, for a star cluster that is 5.0 × 109 years old, MB - MV will be closest to which of the following?
Your Answer is
Correct Answer is J
Explanation
Look at figure 1, when the vertical coordinate is 5×109, the horizontal coordinate is about 0.6