The primary source of energy for a star as it grows in size to become a red giant is
A) hydrogen fusion in the central core.
B) helium fusion in the central core.
C) hydrogen fusion in a shell surrounding the central core.
D) gravitational contraction.
C) hydrogen fusion in a shell surrounding the central core.
You might also like to view...
Pluto's orbit takes it closer to the Sun than Neptune for part of its orbit
Indicate whether the statement is true or false
Which best describes the relationship between two systems in thermal equilibrium?
a. no net energy is exchanged b. volumes are equal c. masses are equal d. zero velocity
A non-conducting sphere of radius R = 7.0 cm carries a charge Q = 4.0 mC distributed uniformly throughout its volume. At what distance, measured from the center of the sphere, does the electric field reach a value equal to half its maximum value?
A) 3.5 cm only B) 4.9 cm only C) 3.5 cm and 9.9 cm D) 3.5 cm and 4.9 cm E) 9.9 cm only
Distant galaxies are
A) growing closer to each other as they encounter the curvature of the universe. B) accelerating away from each other. C) slowing in their dispersal due to the effects of gravity. D) connected to each other by dark energy.