SAT Subject Physics Practice Question 445: Answer and Explanation
6. The drawing represents the results in a Young's double slit interference pattern experiment.
Which letter represents the wavelength of the light?
Correct Answer: D
The correct answer is (D). The relative retardation of the light wave (the letter D in the diagram) is also its wavelength. The bright spots produced on the screen represent n = 1,2,3, etc., whole number values of wavelengths.