(a) Laws of reflection of sound :
1. Angle of incidence is equal to the angle of reflection. ∠i = ∠l
2. Incident wave, reflected wave and the normal lie in the same plane.
(b) Verification of laws of reflection : Take a smooth polished large wooden board and mount it vertically on a table. At right angle to the board fix a wooden screen on each side of the screen place a long, narrow and highly polished tube from inside. Place a watch at the end A. Move the tube B slightly left or right till distinct tick of water is heard. Measure ∠PKN and ∠BKN.
It is found that ∠PKN = ∠BKN. This verifies the laws of reflection.
