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Name: Sankar K.
Status: educator
Age: 30s
Location: N/A
Country: N/A
Date: 7/17/2003
Question:
In many books it is said that a light wave consists electric and magnetic field perpendicular to each other. But light has no charge. How does this electric field exist when light is in vacuum? Why is the electric field in the EM wave not disturbed or deflected in the presence of external electric field? I feel that, the electric field not propagating. I suggest that it is the energy developed by the electric magnetic fields at the location source is propagating.

Replies:
Sankar,

Two things can produce electric effects, an electric charge and a changing magnetic field. Two things can produce magnetic effects, a moving electric charge and a changing electric field. A vibrating electric charge produces changing electric fields and changing magnetic fields. The changing electric field then produces a changing magnetic field and the changing magnetic field produces a changing electric field. These changing fields continue driving each other along, giving energy back and forth to each other until reaching an electric charge. At that point, the field may or may not give its energy to the charge, causing the new charge to vibrate. This is vision.

Dr. Ken Mellendorf
Physics Professor
Illinois Central College


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