
uncertainty in a reading
1. The problem statement, all variables and given/known data
Hi
I need some help with this problem. It reads this way:
The manufacturer of a digital ammeter quotes its uncertainty as plusminus 1.5% plusminus 2 digits.
a) Determine the uncertainty in a constant reading of 2.64A
b) The meter is used to measure the current from a d.c power supply. The current is found to fluctuate randomly between 1.58A and 2.04A. Determine the most likely value of the current, with its uncertainty.
2. Relevant equations
uncertainty as plusminus 1.5% plusminus 2 digits.
3. The attempt at a solution
Solving (a)
2.64 x 1.5% = 0.0396
1.5% x 2 = 0.03
Adding the above =0.0696
The answer in my physics book is plus  minus 0.06A. Can anyone kindly clarify way? I know the number of significant figures determines the uncertainty. Can the answer not be 0.07A? (After rounding up)
Solving (b)
I am not sure how to being. Since uncertainty is the range of values, I decided to find the range
So, 2.041.58 = 0.46A
But not sure how to progress further. Any suggestions? (Please bear in mind I study independently)