The angle between one tube and normal is 400 ,the perfect reflection of sound will take place only when angle between two tubes is…………
For perfect reflection of sound, the angle of the incident sound wave and the reflected sound wave should be equal.
So if we consider the incident angle to be 40° then the angle of reflection will also be 40°.
Thus the angle between the two tubes will be 80°.
You have rated this answer /10