Author Question: At a particular point and instant, the magnetic field component of an electromagnetic wave is 15.0 ... (Read 95 times)

rosent76 · **on:** Jul 29, 2018

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