What is the slit spacing of a diffraction necessary for a 600 nm light to have a first order principal maximum at 25.0°?
Physics · High School · Thu Feb 04 2021
Answered on
To find the slit spacing (d), also referred to as 'grating spacing,' for a diffraction grating that results in a first-order principal maximum at a specific angle, you can use the diffraction grating equation for constructive interference, which is given by:
nλ = d sin(θ)
Where: - n is the order number of the principal maximum (n=1 for first-order principal maximum) - λ is the wavelength of the light (in meters) - d is the slit spacing (also known as grating constant or line spacing) - θ is the diffraction angle where the principal maximum occurs.
Rearranging this equation to solve for d gives:
d = nλ / sin(θ)
Given that λ = 600 nm (1 nm = 10^-9 meters), n = 1 for the first order maximum, and θ = 25.0°, you can plug in the values:
d = (1 * 600 * 10^-9 m) / sin(25.0°)
First, calculate the sine of 25.0°:
sin(25.0°) ≈ 0.4226
Now substitute this value into the equation to solve for d:
d ≈ (1 * 600 * 10^-9 m) / 0.4226 d ≈ (600 * 10^-9 m) / 0.4226
d ≈ 1.419 * 10^-6 m
d ≈ 1420 * 10^-9 m
Expressed in nanometers:
d ≈ 1420 nm