A regulated power supply is set to deliver a voltage of 5.00 V
PHYSICS · Multi-part · A Level · Physics · Measurements and their errors · Measurements and their errors
Problem
A regulated power supply is set to deliver a voltage of 5.00 V. Two digital voltmeters X and Y are used independently to measure this voltage five times each.
Voltmeter X readings (V): 5.04, 4.98, 5.01, 5.02, 4.99
Voltmeter Y readings (V): 5.30, 5.28, 5.32, 5.29, 5.31
Use the data below to evaluate the performance of the two instruments.
(i) For each voltmeter, calculate the mean reading, writing your answer with the proper significant figures.
(ii) For each voltmeter, determine the percentage error of the mean value with respect to the set voltage.
(iii) For each voltmeter, compute the maximum deviation of the individual readings from its own mean and quote this deviation as an indicator of precision.
(iv) Identify which voltmeter gives the higher accuracy and which gives the higher precision, supporting your answer with the numerical results obtained.
(v) Comment on whether the dominant error in each voltmeter appears to be systematic or random and justify your choice briefly.