1. Interference

3. Hearing superposition 1m Same frequency from Signal generator Walk along a path that is one metre away What do you hear?

6. The Interference Pattern

8. What are the factors that affect fringe separation? Fringe separation = distance between bright lines

9. Fringe separation w = separation of the fringes (bright to bright or dark to dark) λ = wavelength of the light s = separation of the two slits D = distance between slits and screen w D s W = λD S

11. Young’s answers

12. Ripple Tank

13. The geometric analysis of Young’s experiment s

14. What is the use of knowing θ ? For it to be in phase (first fringe) θ = sin -1 d/ λ For it to be out of phase θ = sin -1 2d/ λ

15. At the first dark fringe The waves must be in anti-phase λ difference at the point on the wall λ = s sin θ θ = sin -1 2d/ λ θ s θ What is this length? O = s sin θ Opposite Sin θ Hypotenuse s s

16. At the first Bright fringe The waves must be in phase λ difference at the point on the wall λ = s sin θ θ = sin -1 s/ λ s s s

17. What is the use of knowing θ ? For it to be in phase (first fringe) θ = sin -1 d/ λ For it to be out of phase θ = sin -1 2d/ λ