Does anybody know how the power formula goes?  I've been studying and taking 
simulated exams on aa9pw.com.  In his sample questions, he gives the 
questions and the answers but I don't know the formula to get to the right 
answers.  Example:

G4D03:  What is the output PEP from a transmitter if an oscilloscope 
measures 200 volts peak-to-peak across a 50 ohm resistor connected to the 
transmitter output?
Answer is 100 watts

But I don't know how they got that number?  and then there's another one 
exactly the same but with 500 volts and 50 ohms.  And the answer is 625 
watts.

I can't seem to make a formula that will come up with these two answers.  If 
I can find the formula, I think I'll take a crack at the general test.

Help!?

Thanks.

Howard K. Traxler, Technology Specialist
www.TraxlerEnterprises.com