- #1
Dexter Neutron
- 50
- 0
So far I have came to know that when a charge is accelerated the electric field magnitude around the charge changes and the effect is not felt instantaneously. The change in magnitudes of electric and magnetic field travels outwards at speed of light creating the so called EM wave.
So the EM wave originates only due to "the effect not being felt instantaneously". This case would also arise when a charge is not accelerating but moving at a constant speed. For example if there is a charge moving at a constant speed ##v = c/2## in space. At time ##t = 0## the charge comes into existence at origin and we place an observer at a distance ##r = 12 * 10^8 ##metres from the charge. Now it would take electric field a time ##t = 4 seconds## to travel to the observer i.e. the electric field is not felt instantaneously. This would mean that an em wave has traveled from the charge to the observer. In this 4 seconds of time the charge moves by a distance of ##6*10^8## metres which means that the electric field needs to be changed again because ## E \alpha \frac{1}{r^2} ##and since r is changing E must change so again the change in field would take some time to reach the observer which means EM wave is produced traveling from charge to the observer.
The charge is not accelerating but still the EM wave is produced. HOW?
So the EM wave originates only due to "the effect not being felt instantaneously". This case would also arise when a charge is not accelerating but moving at a constant speed. For example if there is a charge moving at a constant speed ##v = c/2## in space. At time ##t = 0## the charge comes into existence at origin and we place an observer at a distance ##r = 12 * 10^8 ##metres from the charge. Now it would take electric field a time ##t = 4 seconds## to travel to the observer i.e. the electric field is not felt instantaneously. This would mean that an em wave has traveled from the charge to the observer. In this 4 seconds of time the charge moves by a distance of ##6*10^8## metres which means that the electric field needs to be changed again because ## E \alpha \frac{1}{r^2} ##and since r is changing E must change so again the change in field would take some time to reach the observer which means EM wave is produced traveling from charge to the observer.
The charge is not accelerating but still the EM wave is produced. HOW?