In a school experiment, two sound sensors are placed 850 m apart. The time taken for a sharp clap to travel from the first sensor to the second is measured six times, giving the following values: 2.50 s, 2.46 s, 2.54 s, 2.51 s, 2.49 s, 2.50 s.
(i) Calculate the average time of travel.
(ii) Using this average time, determine the speed of sound in m/s.
(iii) If the stopwatch has a least count of 0.01 s, calculate the percentage uncertainty in the measured speed (consider uncertainty only in time).