An astronomical telescope has an objective of diameter 20 cm with a focal length of 180 cm. The telescope is used with an eyepiece of focal length 3.0 cm. The magnifying power of the telescope is
A)
360 X.
B)
60 X.
C)
540 X.
D)
7 X.
E)
180 X.
Question 2
Two large, flat, horizontally oriented plates are parallel to each other, a distance d apart. Half-way between the two plates the electric field field has a magnitude E.
If the separation of the plates is reduced to d/2 what is the magnitude of the electric field half-way between the plates? A)
4E
B)
E/2
C)
0
D)
2E
E)
E
