MYP Physics · 10 · multiple choice
The echo travels twice
Sound and oscillation · Original GioPhysics question with a detailed, mark-by-mark answer guide.
- Demand
- recall
- Marks
- 3
- Topics
- 2
- Answer
- Complete
multiple choice3 marks
A student claps 51 m from a large wall and hears the echo 0.30 s later. What speed of sound does this measurement give?
- a
Select and show Select the correct speed and show why the travel distance is not 51 m.
3 marks
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Answer overviewCorrect answer: C — 340 m s⁻¹
01
3 marksa
Select and show Select the correct speed and show why the travel distance is not 51 m.
How to approach it
Predict from the governing principle before looking for a matching option. Then reject alternatives by checking direction, units, limiting behaviour or the physical meaning of each statement.
- 1
Selects option C: the measured speed of sound is 340 m s⁻¹.
- 2
Uses total sound path = 2 × 51 = 102 m because sound travels to the wall and back.
- 3
Calculates speed = 102 ÷ 0.30 = 340 m s⁻¹.
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