PHYSICS · Multi-part · A Level · Physics · Measurements and their errors · Measurements and their errors
Problem
4. In a laboratory setup, two microphones are placed 1.000m apart on a straight line. A sharp clap is produced near one end. An electronic timer displays a time difference of 2.90ms between the arrival of the sound at the two microphones.
The measured distance between the microphones has an uncertainty of ±0.005m, and the measured time difference has an uncertainty of ±0.05ms.
Answer all parts clearly showing your working.
(a) Using the central (mean) readings, calculate the speed of sound in air in ms−1.
(b) Determine the percentage uncertainty in the measured distance.
(c) Determine the percentage uncertainty in the measured time.
(d) Assuming the uncertainties are independent, calculate the percentage uncertainty in the value of speed obtained in part (a).
(e) State the speed of sound with its absolute uncertainty, rounded to an appropriate number of significant figures.