http://www.allaboutcircuits.com/vol_3/chpt_3/11.html

States:
Like any semiconductor device, the zener diode is sensitive to temperature. Excessive temperature will destroy a zener diode, and because it both drops voltage and conducts current, it produces its own heat in accordance with Joule's Law (P=IE). Therefore, one

I may be overlooking something but I've known Joule's Law as H = RI\(^2\)

 

E=RI

That's too short, so here are some more words.
John

 

So the E-Book is wrong and I am wrong?

From Encyclopedia Britannica:

The English physicist James Prescott Joule discovered in 1840 that the amount of heat per second that develops in a wire carrying a current is proportional to the electrical resistance of the wire and the square of the current. He determined that the heat evolved per second is equivalent to the electric power absorbed, or the power loss.

 

Joule's Laws are a pair of laws, not just one.

http://en.wikipedia.org/wiki/Joule%27s_Law

 

Both the ebook and you are correct.

P = I*E -- power (dissipated as heat) equals current multiplied by voltage.
E = I*R -- voltage across an element is current multiplied by resistance.

substitute E back into the power equation

P = I*(I*R)
P = I\(^{2}\)*R = RI\(^{2}\)

 

If it confused someone of my caliber and expertise, It could also confuse a third grader.

It was just a note, but it seemed like a error to me. Seeing a formula I usually equate to Ohms Law with Joules name next to it, threw up a flag. I thought it was a case of the missing exponent.


Thanks for clearing that up.