Skip to main content
GIOPHYSICS
Menu

IGCSE · 3 · multiple choice

Waves · Question 5

Waves · Original GioPhysics question with a detailed, mark-by-mark answer guide.

Demand
routine
Marks
1
Topics
1
Answer
Complete
A student standing in front of a large wallwallstudent165 m
Fig. 5.1A side view of the arrangement. The student stands on level hatched ground on the left, facing a tall wall drawn as a hatched vertical slab standing on the same ground well to her right. A dimension line above her head runs horizontally from the student across to the face of the wall and is labelled 165 m. No sound path is drawn on the figure.
multiple choice1 mark

A student stands 165 m from a large wall and claps once. She hears the echo 1.0 s later. What is the speed of sound in air from her measurement?

  1. A

    165 m/s

  2. B

    247 m/s

  3. C

    330 m/s

  4. D

    660 m/s

Ready to self-mark?Reveal the detailed answer guide
Answer overviewCorrect answer: C — 330 m/s
01

Answer and reasoning

1 mark
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. 1

    The correct choice is C: 330 m/s

  2. 2

    A is the trap and takes about half of all candidates: the sound travels to the wall and back, so the distance is 330 m, not 165 m.

Private on this device

Did your answer earn the marks?

Compare the reasoning point by point, then choose what happens next.