1. Oct 8, 2009

### SANGHERA.JAS

HI,
I wanted to know what is field anyway, Is it wave, particle or some different sort of physical entity.

2. Oct 8, 2009

### Bob_for_short

A field is a function of coordinates and time: f(r,t).

A particle (point-like particle) has three coordinates depending on t: r(t). It is a line in the 3D space.

A filed is normally defined in all points of space.

Example of a scalar filed: pressure in the atmosphere p(r,t).

Example of vector filed: wind velocity in the atmosphere V(r,t).

Last edited: Oct 8, 2009
3. Oct 8, 2009

### SANGHERA.JAS

Mr. Bob, I am very thankful to you about yours response. But sir I am not interested in the mathematical description but rather its physical description. e.g. whether em field really exist, or it is just a mathematical tool.

4. Oct 8, 2009

### Bob_for_short

Yes, the EM field exists: it can be received by a radio, TV, etc. Sound waves are also a good example: we hear them at any place of space.

5. Oct 8, 2009

### SANGHERA.JAS

Thank You Mr. Bob

6. Oct 8, 2009

### HallsofIvy

Staff Emeritus
More correctly, it is waves in the EM-field that are "received" by a radio, not the field itself!

7. Oct 8, 2009

### SANGHERA.JAS

Yes your are right. But question still remains there. What are exact physical phenomenons working behind these so called force fields?

Last edited: Oct 8, 2009
8. Oct 9, 2009

### skippy1729

As for classical fields, one of my teachers, long ago, described them as an "influential domain of a source" (T.K.Ishii). I have always found this to be a satisfying non-mathematical description.

Skippy