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A diffraction grating has 1000 slits per mm. Find the second-order diffraction peak of 400 nm light when illuminated perpendicular to the grating surface. Express your answers in degrees but do not enter the unit.

a) Calculate the angle of diffraction for the second-order peak.

b) Determine the wavelength of light for the first-order diffraction peak.

c) Find the angular separation between adjacent orders.

d) Calculate the distance between the slits on the grating.

1 Answer

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Final answer:

a) The angle of diffraction for the second-order peak is approximately 6.57 degrees. b) The wavelength of light for the first-order diffraction peak is approximately 783.3 nm. c) The angular separation between adjacent orders is approximately 37.67 degrees.

Step-by-step explanation:

a) To find the angle of diffraction for the second-order peak, we can use the formula for the angle of diffraction for a diffraction grating: θ = sin^(-1)(mλ/d), where m is the order of the diffraction peak, λ is the wavelength of light, and d is the distance between adjacent slits on the grating. In this case, m = 2, λ = 400 nm, and d = 1/1000 mm = 1/1000000 m. Plugging these values into the formula gives θ = sin^(-1)(2 * 400 * 10^(-9) / (1/1000000)). Solving for θ gives θ ≈ 0.1146 radians, or approximately 6.57 degrees.

b) To determine the wavelength of light for the first-order diffraction peak, we can rearrange the formula for the angle of diffraction and solve for λ: λ = d * sin(θ) / m. In this case, m = 1, θ = 6.57 degrees, and d = 1/1000 mm = 1/1000000 m. Plugging these values into the formula gives λ = (1/1000000) * sin(6.57 degrees) / 1. Solving for λ gives λ ≈ 783.3 nm.

c) The angular separation between adjacent orders can be found using the formula Δθ = sin^(-1)(mλ/d), where m is the order of one of the peaks and λ is the wavelength of light. In this case, m = 1, λ = 400 nm, and d = 1/1000 mm = 1/1000000 m. Plugging these values into the formula gives Δθ = sin^(-1)(1 * 400 * 10^(-9) / (1/1000000)). Solving for Δθ gives Δθ ≈ 0.6585 radians, or approximately 37.67 degrees.

d) The distance between the slits on the grating can be found using the formula d = 1/(lines per mm). In this case, we are given that there are 1000 slits per mm, so the distance between the slits is d = 1/1000 mm = 1/1000000 m.

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