Two planes of charge with no thickness, A and B, are parallel and vertical. The electric field in the region between the two planes has magnitude

. The electric field in the region to the left of A and the electric field in the region to the right of B may have the magnitudes



a.

0, 0.



b.

.



c.

,



d.

given in any answer above.



e.

given only in answer (a) or (b) above.

---

d

Physics & Space Science

Which of the following claims about the very first stars in the universe would be impossible given our basic picture of the history of the universe?

A) Many of them have exploded as supernovae by now. B) Some of them formed in large clusters. C) Some of them formed in isolation from one another. D) Some may have left behind neutron stars or black holes that still exist in the Milky Way today. E) Some of them had rocky planets around them as they formed.

How much cooler is the universe now (at an age of 4 × 1017 s) than it was at an age of 1 second?

A) Its current temperature is one hundred-millionth (10-8) the temperature at an age of 1 second. B) Its current temperature is one hundred-thousandth (10-5) the temperature at an age of 1 second. C) Its current temperature is one-hundredth (10-2) the temperature at an age of 1 second. D) Its current temperature is one ten-billionth (10-10) the temperature at an age of 1 second.

A glider on an air track is connected by a spring to the end of the air track. If it takes 0.30 s for the glider to travel the distance of 12 cm from one turning point to the other, its amplitude is

A. 12 cm B. 6 cm C. 24 cm D. 36 cm E. 3.6 cm F. We are not given enough information to answer.

How might the most common occurring stars be described, based on our stellar neighborhood?

A) white dwarfs B) K giants C) G main sequence D) A main sequence E) M main sequence