1. Properties of waves

2. RIPPLE TANK

3. A ripple tank consists of a rectangular try with glass bottom
A ripple tank consists of a rectangular try with glass bottom. This tray is placed approximately at a height equal to ½ m above the surface of table by the help of four legged frame, on which tray is placed containing water having light source above and white screen below to receive the wave images.

4. The behavior of water can be studied in a ripple tank
The behavior of water can be studied in a ripple tank. The circular pulses are obtained by dipping dipper in water and straight pulses are obtained by ruler. Continuous pulses are ripples are generated by an electric motor.

5. REFLECTION of waves WITH THE HELP OF RIPPLE TANK

7. By using ripple tank the reflection of water waves can be observed.
Straight waves are generated by the help of oscillating plane of ripple tank.
A plane surface is placed in the path of these waves it acts like hurdle, and the path of waves is changed. It is called reflection of waves.

8. Angle of incidence = Angle of reflection
. It is possible to measure the angle of incidence and angle of reflection.
These two angles are found to be equal, according to law of reflection.
Angle of incidence = Angle of reflection
< i = < r
AO is incident and OB is reflected direction of motion of water waves.

9. REFRACTION OF WATER WAVES

11. When waves from one medium enter in the second medium at some angle their direction of travel may change. This phenomenon is called refraction of waves.
A plastic sheet is placed at an angle to the incoming plane waves to create a region of shallow water.

12. The difference in depth of water causes a change in speed of wave.
The change in the direction due to change in velocity is called refraction.
n = Sin < I / Sin < r

13. DIFFRACTION OF WATER WAVES

15. Two obstacles with narrow gap between them are placed in the path of plane waves in a ripple tank.
The width of gap is compare able to wave length of waves. The waves passing through the gap spread out in all directions.
The wave fronts are circular. The spreading or bending of waves is called diffraction.