You are here:

Physics/EM radiation &



I read that light is an electro magnetic wave. Does that mean that light can be produced using electricity and magnetism. Tube lights, neon lamps produce lights without any magnets involved. Please explain.
Also I read that mass can be converted to energy, if a camphor evaporates, the mass of the camphor is lost but we don't see much energy as indicated by E=mc^2 getting released. please clarify

sorry for such basic questions..

ANSWER: > Does that mean that light can be produced using electricity and magnetism?


When you analyze the equations of electricity and magnetism, you find that a vibrating charge (such as an electron) produces a vibrating electric field (E-field). This vibrating E-field then produces a vibrating magnetic field (B-field). This vibrating B-field then produces a vibrating E-field, and the process starts all over. You end up with an electromagnetic wave that propagates itself, even through a vacuum. This is exactly what light is.
This gif
shows these fields as they move through space.

The entire process starts with vibrating electrons; thus, no magnets are needed at all.

> if a camphor evaporates, the mass of the camphor is lost

Not exactly. The mass of the camphor CHANGES from a liquid state to a gaseous state, but none of its mass disappears. If you add up all the gaseous molecules of camphor after it evaporates, you'll find they exactly equal the number of liquid camphor molecules prior to evaporation.

---------- FOLLOW-UP ----------


Thanks for your reply. If light consists of both electric and magnetic field, there should be minute magnetism exhibited by light. Can we find the magnetic effect in light?.

Is E=mc^2 measured and scientifically proved or is it theoretical. Also in CERN LHC, I read that they are making two protons to collide one another, how are they handling enormous amount of energy released?

> Can we find the magnetic effect in light?

If there is any effect of the vibrating magnetic field on matter, it is overwhelmingly swamped by the effects of the vibrating E-field. This is because B-fields only affect moving charges and, within most matter, the net charge flow is zero. E-fields, on the other hand, can affect both moving and stationary charges. Thus, when an EM wave hits matter, the effects of the E-field on matter are so much greater than any effects of the B-field that the latter effects can be disregarded. I have been unable to find any measurable effects of the B-field in an EM wave.

> how are they handling enormous amount of energy released?

Since the particles that are moving are protons, it's not that much energy on a macroscopic level. The kinetic energy of a proton in CERN is no more than the kinetic energy of a mosquito flying through the air.
On an atomic level, that's an unbelievable amount of energy; on a human level, it's not much.


All Answers

Answers by Expert:

Ask Experts




I can help with understanding physics that does not involve eggs. I will NOT help with academic or professional questions, which are NOT limited only to homework. Please do not waste your time by asking a question that comes out of ANY kind of academic, professional, or business matters.


Have been fascinated by physical laws ever since I learned, at age seven, that magnets work under water. My study continued through college and has not ceased even after I retired.

B.A. in Physics (with honors) from University of California at Berkeley.M.A. in Physics (with honors) from University of Texas Austin.

©2017 All rights reserved.