A very long solenoid has 1.0 106 turns per meter and a ...

[jon_i]

A very long solenoid has 1.0  106 turns per meter and a cross-sectional area of 2.0  106 m2. A short, secondary coil with 1.0  103 turns is wound over the solenoid's midpoint.
 
  What emf is induced in the secondary coil if the current in the solenoid is changing at a rate of 4.0 A/s? A) 1.0 V
  B) 2.7 V
  C) 1.6 V
  D) 0.52 V
  E) 4.4 V

Question 2

What POWER lens placed next to a lens of 25. cm focal length would produce a combination with an effective INFINITE focal length?
 
  What will be an ideal response?

[samiel-sayed]

Answer to Question 1

A

Answer to Question 2

-4.0 Diopters

[jon_i]

Thank you!

[samiel-sayed]

Always glad to help...