KS3 Questions on Sound
Q8. A teacher shines a laser beam onto a classroom window. It reflects off the window and onto a screen.
(a) On the diagram below, continue the laser beam to show its path as it reflects off the window and onto the screen. Use a ruler. Add arrows to show the direction of the laser beam.
See diagram
- the angles of incidence and reflection must be equal
- the rays must be continuous and straight with an arrow in the correct direction
2 marks
(b) When a pupil plays her flute in the classroom the window vibrates.
(i) When a pupil plays her flute in the classroom the window vibrates.
Give the reason for this.
The sound waves travel to the window in the form of vibrations of air molecules.
The air molecules near to the window receive the vibration and hit the window thereby passing on on the vibration.
(ii) When the window vibrates, what happens to the laser beam that is reflected off the window?
The beam will vibrate or jump about
3 marks
(c) The teacher places a microphone near the pupil as she plays her flute.
The diagram below shows the pattern on an oscilloscope screen.
The pupil then plays her flute at a higher pitch and more quietly.
Which diagram below shows the pattern that would be seen on the oscilloscope?
1 mark
maximum 6 marks
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