Calculating Max Output Power from a 12V Battery w/ 6 Ohm Resistance

[Manelectro]

I'm having a tough time wrapping my head around something that seems so simple. The Question is:

What is the maximum output power from a 12 volt battery that has an internal resistance of 6 ohm ?

The answer from this books is 6 W?

My formula
First I need to find the current
I = V/R so 12volt/6 ohm = 2 ampere

When is use this formula
P = VI, 12Vx2A = 24Watt,

The next question is:
On an oscilloscope display of a pure sine wave , the peak to peak value is 7 volts. The average value of the display voltage is about:

A. 6.36 volt
B.3.18 volt
C. 0 volt
D. 2.23 volt

The answer from this book is 0 volt.

The peak to peak voltage is 7/2 = 3.5V this peak voltage

But by calculation Vaverage = 2 x 3.5/ pi = 2.228 or 2.23 V for sine wave or AC wave formula.

If the average value were taken over the whole cycle then the result would be zero value.

Thank you,
Azman

 

[Manelectro]

Anybody can answer this question. where the math guru...anyway thank :)

 

[Manelectro]

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