Physics Question

[GML3G0]

http://img258.imageshack.us/img258/1527/untitled6kk.png

Those are the two questions, and the anwers are D and E respectively.

I'm pretty sure #3 is D because the strength of the electric field is inversely proportional to the distance, but I'm not entirely sure. This review book doesn't do a good job of explaining it to me, and this isn't part of the school curriculum, so I'm kind of learniong this stuff on my own. As for 4, I have no idea why the answer is E. Can anyone explain please? Thanks a lot.

EDIT: This review book really sucks ass. I scored an 800 on the practice test they included. The questions seem so much easier than the ones on the actual test.

 

[Heisenberg]

Yes, #3 is D since the electric field strength is inversely proportional to the square of the distance. For #4, an electron is negatively charged and will be attracted to a positive charge. Since the electric field from a point charge is radially outward, only at position E will the force be directed only straight up. Any other position and it would have components in other directions.

 

[spidey07]

D because it's farther
E becuse it is in line with the positive charge (inline with the top)

 

[GML3G0]

Oh, doh... For some reason I read it as "out of the page" as in straight up out of the page.

Into the page, out of the page, toward the top of the page, toward the bottom of the page. Grrr... OK... :smacks forehead;