While surveying a deep well, a student drops a sharp sound pulse and records the echo time twice—once in the afternoon and once at night. The physical depth of the well obviously remains the same.
(i) In the afternoon the temperature is 35∘C and the echo time is 2.00s. Determine the depth of the well.
(ii) At night the temperature falls to 15∘C. Calculate the echo time that should now be observed.
(iii) If the student, unaware of the temperature change, still uses the afternoon value of the speed of sound when analysing the night-time echo, compute the percentage error in the depth obtained.