Two wavelengths, 800 nm and 600 nm, are used separately in single-slit diffraction experiments.The diagram shows the intensities on a far-away viewing screen as function of the angle made by the rays with the straight-ahead direction.If both wavelengths are then used simultaneously, which point corresponds to the smallest angle at which the light on the screen is purely 800-nm light?
A)A
B)B
C)C
D)D

Question

Two wavelengths, 800 nm and 600 nm, are used separately in single-slit diffraction experiments.The diagram shows the intensities on a far-away viewing screen as function of the angle made by the rays with the straight-ahead direction.If both wavelengths are then used simultaneously, which point corresponds to the smallest angle at which the light on the screen is purely 800-nm light? 
A)A 
B)B 
C)C 
D)D

Quizplus · Accepted Answer

According to the diagram, point C corresponds to the maximum intensity for 800 nm light and minimum intensity for 600 nm light. Therefore, if both wavelengths are used simultaneously, point C would correspond to the smallest angle at which the light on the screen is purely 800-nm light.

Two Wavelengths, 800 Nm and 600 Nm, Are Used Separately