The quantity called the "enclosed mass" M(

A) concentrated in the center
B) spread out over a large volume
C) distributed in the shape of a doughnut, with a hole in the center
D) impossible to say

---

A

Physics & Space Science

Which statement about pulsars is not thought to be true?

A) All pulsars are neutron stars, but not all neutron stars are pulsars. B) Pulsars can form only in close binary systems. C) A pulsar must have a very strong magnetic field and rotate quite rapidly. D) Pulsars are kept from collapsing by neutron degeneracy pressure.

What is the average translational kinetic energy of an ideal gas at 819K The Boltzmann constant is 1.38 × 10-23 J/K

A) 1.70 x 10-20 J B) 5.65 x 10-21 J C) 1.13 x 10-17 J D) 3.77 x 10-19 J

The percentage of 235U, as a fraction of the total uranium content, in a uranium fission bomb is closest to

A) 50 percent. B) 20 percent. C) 1 percent. D) 90 percent. E) 5 percent.

From hottest to coolest, the order of the spectral types of stars is

A) OBAFGKM. B) OBAGFKM. C) ABFGKMO. D) OMKGFBA. E) ABCDEFG.