Question

scientists have found as a light source moves toward a stationary observer, 1 point the wavelengths of light source appear shorter longer higher lower which of the following stars is the brightest? 1 point the hertzsprung - russell diagram blue or blue - white white yellow red - orange red rigel deneb supergiants north star (polaris) betelgeuse zeta eridani antares spica main sequence canopus regulus aldebaran algol capella mizar arcturus mira vega sirius procyon pollux altair giants sun alpha centauri a tau ceti alpha centauri b epsilon eridani sirius b white dwarfs procyon b barnards star van maanens star average surface temperature (°c) increasing absolute magnitude (brightness)

Explanation:

1. For the first question, when a light - source moves towards a stationary observer, due to the Doppler effect, the wavelengths of the light source appear shorter. This is because the waves are compressed as the source approaches.
2. For the second question, on the Hertzsprung - Russell Diagram, the higher up on the absolute magnitude (brightness) axis a star is, the brighter it is. Among the stars shown, Canopus is one of the stars located higher up on the absolute magnitude axis compared to many others.

Answer:

1. shorter
2. Canopus