1) Cepheid Variables are useful for determining the distance to galaxies because the length of a cycle from maximum brightness to minimum brightness, and back to maximum brightness, is
a) directly related to the star's average luminosity
b)inversely related to the star's average luminosity
c) directly related to the star's distance from Earth.
d) inversely related to the square of the star's average radius.
e) inversely related to the star's distance from the core of the milky way.
2) Type Ia supernovae are useful for determining the distance to galaxies because,
a) they always reach the same minimum brightenss.
b) they always reach the same maximum birhgtness.
c) their true brightness is inversely related to the square of the length of their brightness cycle
d) their true brightness is inversely related to the length of their brightness cycle
e) their true brightness is directly related to the square of the length of their brightness cycle.
Thank you!
a) directly related to the star's average luminosity
b)inversely related to the star's average luminosity
c) directly related to the star's distance from Earth.
d) inversely related to the square of the star's average radius.
e) inversely related to the star's distance from the core of the milky way.
2) Type Ia supernovae are useful for determining the distance to galaxies because,
a) they always reach the same minimum brightenss.
b) they always reach the same maximum birhgtness.
c) their true brightness is inversely related to the square of the length of their brightness cycle
d) their true brightness is inversely related to the length of their brightness cycle
e) their true brightness is directly related to the square of the length of their brightness cycle.
Thank you!
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1-A 2-B