The phase velocity of a plane wave given by Ex = E0 cos (ωt – βz) with a frequency of 5.0 GHz and a wavelength in the material medium of 3.0 cm is:

The phase velocity of a plane wave given by Ex = E0 cos (ωt – βz)

1.	The phase velocity of a plane wave given by Ex = E0 cos (ωt – βz) with a frequency of 5.0 GHz and a wavelength in the material medium of 3.0 cm is:
A.	3.0 × 108 m/sec
B.	1.5 × 108 m/sec
C.	5 × 108 m/sec
D.	None
Answer» C. 5 × 108 m/sec