# Poynting vs. Current

1. Mar 11, 2015

### Imabioperson

What is the relationship between Current and the Poynting Vector? In General Physics, I was stumped by the focus on the relationship between Voltage, Current and resistivity. It appears to me that Energy transfer should be the focus. But if this is true, what is the significance of current, and how are all of these terms related to one another? As usual, everything seems to be related to everything else.. I have yet to take anything higher than a bit of Calc II. It seems that diff eq. will be necessary if i wish to pursue topics like this, in any greater depth. Any thoughts regarding these things?

2. Mar 12, 2015

### Pierce610

The Poynting vector is the product E x H and it gives the intensity of the electromagnetic wave.
It is also true that an electromagnetic induction in a coil generates a current which is proportional to the magnetic field.

3. Mar 14, 2015

### gleem

Of course energy transfer or Power is important. For current electricity power is I*V. but for various reason both current and voltage may be a more important consideration say for example in an electromagnet current is a factor of concern. In the measurement or detection of physical phenomena a voltage from a transducer might be of concern. The Poynting vector tells us the of energy in an electromagnetic field that is being conveyed.. In current electricity power is of concern when efficiency in power transmission is of importance. It is of concern in determining if equipment using current electricity is capable of using or transferring that energy safely, say without overheating.