Can anyone verify this math? MC 2205 Watt Scale

[bodonnell]

Can anyone verify this math? If I'm looking at a log scale .02, .2, 2, 20, 200 on my amp's watt meter: The location of 100, starting with a datum of 2, would be log(100)-log(2) = 1.7 or roughly 2/3 between 2 and 200.... yes?

Thanks!

 

[Malcolm Irving]

If we take the logs of 2, 20, 200 we get their linear position on the scale:
Log2 = 0.3
Log20 = 1.3
Log200 = 2.3
So 20 is half way between 2 and 200, as expected.
Now Log100 = 2
So the position for 100 on the scale as a fraction of the distance between 2 and 200 is
(2-0.3)/(2.3-0.3) = 0.85

 

[bodonnell]

Oh I actually meant between 20 and 200, looking over your answer and changing it for between 20 and 200: (2-1.3)/(2.3-1.3)=.7 so yes, same difference!