Fusion in giant stars takes us all the way to iron before a Type II supernova occurs. Why did it stop with helium in the far more energetic Big Bang?
What will be an ideal response?
The expansion of the Big Bang cooled the temperature to below 100 million K by the time the helium abundances could have allowed carbon production to start.
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Compared to the Milky Way, how many stars are contained in the most massive galaxies?
A) two to three times as many B) tens of times as many C) hundreds of times as many D) thousands of times as many E) millions of times as many
An ac circuit has a 20 
F capacitor, an 80 mH inductor, and a 60 
resistor in series. If the voltage source has an angular frequency of 1000 rad/s, what is the phase constant for the circuit?
A. 27
B. 53
C. 45
D. 63
E. 88
The coil of a generator is rotated twice as fast keeping all other factors constant. What happens to the value of the maximum induced emf?
A) It stays the same. B) It is reduced by a factor of 2. C) It is increased by a factor of 2. D) It is increased by a factor of 4. E) It is reduced by a factor of 4.
Which of the following is considered by biologists to be a likely place where life might have first arisen on Earth?
A) on land surfaces that got moderately heavy rainfall B) in hot water near undersea volcanoes C) deep in Earth's core D) on meteorites that landed on Earth