An object is placed 15.0 cm to the left of a double-convex lens ...

[Diane]

An object is placed 15.0 cm to the left of a double-convex lens of focal length 20.0 cm. The image of this object is located
 
  A) 60.0 cm to the right of the lens.
  B) 60.0 cm to the left of the lens.
  C) 8.57 cm to the right of the lens.
  D) 8.57 cm to the left of the lens.
  E) 30.0 cm to the left of the lens.

Question 2

A huge (essentially infinite) horizontal nonconducting sheet 10.0 cm thick has charge uniformly spread over both faces. The upper face carries +95.0 nC/m2 while the lower face carries -25.0 nC/ m2.
 
  What is the magnitude of the electric field at a point within the sheet 2.00 cm below the upper face? (0 = 8.85  10-12 C2/N  m2) A) 0.00 N/C
  B) 3.95  103 N/C
  C) 6.78  103 N/C
  D) 7.91  103 N/C
  E) 1.36  104 N/C

[nickk12214]

Answer to Question 1

B

Answer to Question 2

C

[Diane]

TYSM

[mochi09]

Wow, this really help