Why does the Main Sequence part of a star's life end?
A: Much of the mass of the star has evaporated
B: The Hydrogen in the core is exhausted
C: The Helium in the core is exhausted
D: The temperature drops so that nuclear reactions are no longer possible
E: The gravitational force is no longer large enough to balance the pressure
Ans: B: The Hydrogen in the core is exhausted
You might also like to view...
What part of the Apollo spacecraft actually returned to Earth?
a. descent rocket b. lunar module c. rocket boosters d. command module e. support stage
Constant Acceleration Kinematics: A soccer ball is released from rest at the top of a grassy incline. After 6.4 seconds the ball has rolled 91 m with constant acceleration, and 1.0 s later it reaches the bottom of the incline.(a) What was the ball's acceleration?(b) How long was the incline?
What will be an ideal response?
When sound travels faster at ground level than higher in the air, sound tends to bend
A) upward. B) downward. C) neither of these
A conclusion of the Michelson-Morley experiments was that
A. interference of EM-waves does not happen. B. the ether doesn't exist. C. Galilean relativity holds. D. light has momentum. E. light has no momentum.