# Logarithmic UncertaintyWatch

#1
Suppose . How to find absolute uncertainty for ?

I know two methods which are as follows:

1)

2)

Both methods produce approximately the same answers. Which one do I use? Or does it not matter? (For CIE exam board)
Last edited by esrever; 1 month ago
0
1 month ago
#2
V = 1.9 + 0.1
Vmin = 1.8
Vmax = 2.0

log(V) = (log(Vmax) + log(Vmin))/2
Absolute uncertainty = (log(Vmax) - log(Vmin))/2

log(V) is the average of the max and min, and your uncertainty is half the difference between the max and min.
0
#3
(Original post by Brain Damage)
V = 1.9 + 0.1
Vmin = 1.8
Vmax = 2.0

log(V) = (log(Vmax) + log(Vmin))/2
Absolute uncertainty = (log(Vmax) - log(Vmin))/2

log(V) is the average of the max and min, and your uncertainty is half the difference between the max and min.
Makes sense. Thanks!
0
1 month ago
#4
(Original post by esrever)
Suppose . How to find absolute uncertainty for ?

I know two methods which are as follows:

1)

2)

Both methods produce approximately the same answers. Which one do I use? Or does it not matter? (For CIE exam board)
It does not matter.

But your method 1 should be replaced by Brain Damage method:

0
#5
(Original post by Eimmanuel)
It does not matter.

But your method 1 should be replaced by Brain Damage method:

Thanks!
0
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