At a particular point and instant, the magnetic field component ...

[rosent76]

At a particular point and instant, the magnetic field component of an electromagnetic wave is 15.0 T. What is the magnetic energy density of this wave at that point and instant?
 
  (c = 3.00  108 m/s, 0 = 4  10-7 T  m/A, 0 = 8.85  10-12 C2/N  m2 )
  A) 4.47  10-4 J/m3
  B) 9.72  10-5 J/m3
  C) 2.26  10-4 J/m3
  D) 8.95  10-5 J/m3
  E) 1.79  10-4 J/m3

Question 2

If a camera lens lets in an amount of light I when it is set to f/4, then how much light will it let in when it is set to f/8?
 
  A) I/4 B) 16I C) 2I D) 4I E) I/2

[jessofishing]

Answer to Question 1

D

Answer to Question 2

A

[rosent76]

TYSM

[nyrave]

Thanks for the timely response, appreciate it