Yellow Light Is Viewed by Reflection from a Thin Vertical $\lambda$

question 47

Multiple Choice

Yellow light is viewed by reflection from a thin vertical soap film.Let $\lambda$ be the wavelength of the light within the film.Why is there a large dark space at the top of the film?

• A)no light is transmitted through this part of the film
• B)the film thickness there is \(\lambda\)/4
• C)the light reflected from exactly one of the two surfaces undergoes a 180\(\lambda\) phase change
• D)the film is too thick in this region for thin film formulas to apply
• E)the reflected light is in the infrared