Interference was observed in an interference chamber while air was present. Now the chamber is evacuated and the same light is used. A careful observer will see:
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Question

Interference was observed in an interference chamber while air was present. Now the chamber is evacuated and the same light is used. A careful observer will see:

G1 Physics · Accepted Answer

Step 1: Wavelength in medium λ = λ₀/n. Step 2: Removing air decreases n slightly toward 1; consequently λ increases slightly. Step 3: Fringe width β = λD/d therefore increases slightly. Final answer: (D) larger fringe width.