With the previous problem in mind, now consider things spread across space at a given moment in time. Each wave separately would result in an irradiance distribution I₁ and I₂. Plot both on the same space axis and then draw their sum I₁+ I₂. Discuss the meaning of your results. Compare your work with Fig. 7.16. What happens to the net irradiance as more waves of different frequency are added in? Explain in terms of the coherence length. Hypothetically, what would happen to the pattern as the frequency bandwidth approached infinity?

 Fig. 7.16

E E2 (a) E(x) (b) Am = E,(x) (c) 4E 1 beat /(A- ) 2E Ejx) (d)