Three originally uncharged infinite parallel planes are arranged ...

[Alygatorr01285]

Three originally uncharged infinite parallel planes are arranged as shown. Then the upper plate has surface charge density placed on it while the lower plate receives surface charge density . The net charge induced on the center plate is
 
   

   
  a.
  0.
   
  b.
  /2.
   
  c.
  +/2.
   
  d.
  .
   
  e.
  +.

Question 2

A positive point charge q is placed at the center of an uncharged metal sphere insulated from the ground. The outside of the sphere is then grounded as shown. Then the ground wire is removed. A is the inner surface and B is the outer surface. Which statement is correct?
 
   

   
  a.
  The charge on A is q; that on B is +q.
   
  b.
  The charge on B is q; that on A is +q.
   
  c.
  The charge is on A and on B.
   
  d.
  There is no charge on either A or B.
   
  e.
  The charge on A is q; there is no charge on B.

[ririgirl15]

Answer to Question 1

a

Answer to Question 2

e

[Alygatorr01285]

Thanks for the timely response, appreciate it

[patma1981]

Wow, this really help