Monochromatic light is normally incident on a diffraction grating.The m^th order line is at an angle of diffraction $\theta$and has width w.A wide single slit is now placed in front of the grating and its width is then slowly reduced.As a result: A)"both $\theta$and w increase" B)"both$\theta$and w decrease" C)"$\theta$remains the same and w increases" D)"$\theta$remains the same and w decreases" E)"$\theta$decreases and w increases"

Question

Quizplus · Accepted Answer

When a wide single slit is placed in front of the diffraction grating, the intensity of the diffraction pattern decreases but the width of the central maximum increases. This means that the angle of diffraction for the mth order line remains the same (i.e. F1F1F1S1F1F1F10F1F1F1S1F1F1F10remains the same) but the width of the mth order line (w) increases.

Monochromatic Light Is Normally Incident on a Diffraction Grating θ\thetaθ And Has Width W

Monochromatic Light Is Normally Incident on a Diffraction Grating $\theta$ And Has Width W