Light from sources A and B passes through the same diffraction grating and falls on a distant screen.If A produces a first-order bright spot at 30° and B produces one at 60°,then the wavelength of the light from B must be twice as great as the wavelength of the light from B.

Question

Quizplus · Accepted Answer

The statement is incorrect because the angle of diffraction is related to the wavelength by the equation d*sin(θ) = m*λ, where d is the grating spacing, θ is the angle, m is the order, and λ is the wavelength. If B produces a bright spot at 60° and A at 30°, the wavelength of B is not necessarily twice that of A; it depends on the sine of the angles, not the angles themselves.

Light from Sources a and B Passes Through the Same