Multiple choice

A stone is dropped into a well in which the level of water is h at the top of the well. If v is velocity of sound, the time T after which the splash is heard is given by

  1. T = (2h/v)

  2. T = (2h/g)1/2 + (h/v)

  3. T = (h/g)1/2 + (h/v)

  4. T = (2h/g)1/2 + (v/g)

  5. T = (2h/g) + (h/v)
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

 The stone is dropped into the well. So it travels a distance of h, and after falling into the water, sound comes out of the well after travelling distance h with velocity v. Time (t1) taken by the stone to travel the height h down the well Applying the equation, -h = (1/2)(-g)(t1)2t1 = (2h/g)1/2 Now after falling into the water, sound travels the distance h upwards with speed v Time taken by the sound to come out of the well t2 t2 = (h/v) (Time = Distance/ Speed) Total time taken T = t1 +t2 T = (2h/g)1/2 + (h/v) (Correct Answer)

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