If a diffraction grating is heated (without damaging it)and therefore expands,what happens to the angular location of the first-order maximum?
A)It moves toward the centerline.
B)It moves away from the centerline.
C)It doesn't change.

Question

Quizplus · Accepted Answer

The angular location of the first-order maximum is given by the equation: sinθ = λ/d, where θ is the angle between the incident beam and the direction of the diffracted beam, λ is the wavelength of the light, and d is the spacing between the lines of the grating. If the grating expands due to heating, the spacing d increases, which means that sinθ decreases. Since sinθ is proportional to the angle θ, this means that the angle of the first-order maximum decreases (moves toward the centerline). Therefore, choice A is the best answer.

If a Diffraction Grating Is Heated (Without Damaging It)and Therefore