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
E) E

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 
E) E

Quizplus · Accepted Answer

From the diagram, we can see that point C corresponds to the smallest angle where the intensity curve for 800 nm is at its maximum, indicating maximum diffraction for this wavelength. Therefore, when both wavelengths are used simultaneously, point C corresponds 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