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1. Sound gets reflected from

2. Reflection of sound follows the same laws as

3. The direction of incident sound, reflected sound, and the normal all lie

4. To reflect sound effectively, the obstacle must be

5. Which instrument can demonstrate the reflection of sound?

7. The sound which we hear after reflection from a distant surface is called

10. The rolling of thunder is due to

11. The persistence of sound due to repeated reflection is called

12. Excessive reverberation in halls is

13. Reverberation in auditoriums is reduced by using

14. Materials like compressed fibreboard and draperies are used in halls because they

15. The distance of a reflecting surface from the source can be found using

16. In the megaphone, sound is made to travel

17. The stethoscope works on the principle of

18. Why are the ceilings of concert halls curved?

19. What is the purpose of a curved sound board behind the stage?

20. Which of the following uses multiple reflections of sound?