1

Phase different due to time (Beat)p = po sin(kx – wt)

p = po sin(wt)

fbeat = Δf

2

Phase difference due to Pathp = po sin(kx – wt)

Φ=kx2 – kx1

3

Standing Waves

4

Standing Wave (String)Fixed Both Ends

λ=2L/n

Free One End

λ=4L/n

5

Standing Wave (sound)Open Both Ends

λ=2L/n

Open One End

λ=4L/n

6

Dropping stone in well

7

Special Rays (pick your favorite two)

1. Ray parallel to central axis, reflect through focal

2. Ray reflects from mirror after passing through focal

3. Ray passes through center of curvature and returns along itself

4. Symmetric reflection

8

Is it real?