Here's my question: If light is an electro-magnetic wave, with oscillating magnetic and electric fields, wouldn't light interfere with the free electrons flowing (slowly) in a wire, as the electric fields of the EM wave meet the electrons? Would this then lead to a change in the current measured in the wire?
The picture in my mind is where light is approaches and touches a live wire, perpendicular to its surface. Here's an old-fashioned PAINT in action.
One of my assumptions is that light can penetrate a live (i.e. with current) wire, in the same way that light penetrates the material in the photoelectric effect from which electrons are emitted.
Here are a two guesses to my own question.
- [in terms of EM waves] Since the electric fields of the EM wave are oscillatory - the electric field increases in one direction, decreases, then flips in direction - the journey of the free electrons will only be disturbed a little in one direction and then in the other, to no net effect. Thus the current - as an ammeter would help measure - will be unaffected.
- [in terms of physical "intuition", which sometimes is violated in physics!] Since, like how I get warm while sitting under the blazing sun, the wire would be heated by the light, the free electrons will also absorb this heat and so travel with greater kinetic energy. The reading on the ammeter will register an increase in current.
These two guesses reach two mutually exclusive conclusions. Hence my angst and need for your - the reader's - help!
I have a premonition that I have some hidden assumptions that need uprooting ... so do your best, reader!
Note: A10 is a ref number for my own notes. Edit: I added Would this then lead to a change in the current measured in the wire? to my question.