How Do You Determine Which Battery Has the Most Stored Charge?

[Lildon]

Homework Statement

Which of the following batteries has the most stored charge? Their ratings are shown below. Explain your answer.
a) 12V, 500mAh
b) 1.2V, 1200uAh
c) 6V, 3.14159x10e17 electrons
d) 6V, 0.01MAh

2. The attempt at a solution
I think the answer is d because 0.01MAh = 10,000Ah. I'm not sure if this is even right or how to explain it. I haven't really been taught anything about this and all of my experience is from searching the internet for information.

 

[sandy.bridge]

Hint: the higher the ampere-hour, the longer the battery will last.

 

[technician]

The question asks which battery has the most charge.
Ah means Amps x hours which means (coulombs/sec) x hours
which gives charge = (coulombs/sec) x hours x 60 x 60

 

[Lildon]

That means the answer would be D because it has the highest Amp-hours. So the amount of volts has no affect on stored charge?

 

[NascentOxygen]

There are a few things about this question. First, electrochemical cells don't store charge, they store energy in the form of chemical energy. But I know what they mean.
Second, it is obvious here (I think), but often ratings are printed carelessly, and M may sometimes stand for milli-, you can't always assume manufacturers mean mega-. To manufacture a battery rated at 10,000 Ah would make it a colossal size. Maybe something from a submarine?

Volts is not a measure of the current you can draw, in the way it's meant here. So it is only amp-hour capacity that you need to consider.

 

[technician]

I agree...voltage has nothing to do with the amount of charge that can be obtained.
Ah tell you how many coulombs of charge are available.
Voltage tells you how much ENERGY can be obtained per coulomb