1. Grab the nearest book.
2. Open the book to page 123.
3. Find the fifth sentence.
4. Post the text of the next 4 sentences on your blog along with these instructions.
5. Don't you dare dig for that "cool" or "intellectual" book in your closet! I know you were thinking about it! Just pick up whatever is closest.
From Electrical Fundamentals, War Dept. technical manual TM 1-455 10 August 1944
Power is essentially a function of voltage and current (ExI).
The Transformer is a relatively efficient apparatus and in many cases the transformer losses can be neglected.
In such cases EpIp=EsIs.