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Multiple Choice
A light is used to illuminate a diffraction grating with . What is the angle, measured from the central maximum, to the m=3 bright fringe?
A
54°
B
61°
C
68°
D
72°
E
46°
Verified step by step guidance
1
First, understand the problem: We are dealing with a diffraction grating, which is an optical component with a regular pattern that splits and diffracts light into several beams. The problem asks for the angle to the m=3 bright fringe using a light of wavelength 480 nm and a grating with 500 lines/mm.
Convert the grating density from lines per millimeter to meters. Since there are 1000 millimeters in a meter, the grating density is 500,000 lines/m. The distance between adjacent slits (d) is the reciprocal of this value: d = 1 / (500,000 lines/m).
Use the diffraction grating formula to find the angle θ for the m-th order maximum: d * sin(θ) = m * λ, where d is the distance between slits, m is the order of the maximum (m=3 in this case), and λ is the wavelength of the light (480 nm, which is 480 x 10^-9 meters).
Rearrange the formula to solve for the angle θ: sin(θ) = (m * λ) / d. Substitute the known values into this equation: sin(θ) = (3 * 480 x 10^-9 m) / (1 / 500,000 m).
Finally, calculate the angle θ by taking the inverse sine (arcsin) of the result from the previous step. This will give you the angle in radians, which can be converted to degrees if necessary.