 #1
songoku
 2,114
 278
 Homework Statement:

Which of the following statements is correct?
a. Checking for zero error in voltmeter before measuring a voltage will help to reduce random error
b. Measuring the timing of a larger number of oscillations will help to reduce the fractional uncertainty of the period
c. Plotting a graph of voltage and current readings for an ohmic device and using its gradient to find resistance will help to eliminate random error
d. In the measurement of the diameter of a sphere, taking more readings and finding the average value of these readings will help to reduce the fractional uncertainty of the diameter
 Relevant Equations:
 Not sure
I know option (a) and (c) are wrong but I don't know the difference between option (b) and (d) because I think they are the same (taking average to get more accurate reading and reduce random error).
My guess is (b) because I think for (d) the fractional uncertainty maybe can stay the same because taking average will reduce random error (the uncertainty) and also can reduce the reading of the diameter (I mean the average of 5 readings will be smaller than average of 4 readings) so the fractional uncertainty (##\frac{\Delta ~ diameter}{diameter}##) stays the same
I am not sure whether my reasoning is correct. Thanks
My guess is (b) because I think for (d) the fractional uncertainty maybe can stay the same because taking average will reduce random error (the uncertainty) and also can reduce the reading of the diameter (I mean the average of 5 readings will be smaller than average of 4 readings) so the fractional uncertainty (##\frac{\Delta ~ diameter}{diameter}##) stays the same
I am not sure whether my reasoning is correct. Thanks