Complete Question
You are performing a double slit experiment very similar to the one from DL by shining a laser on two nattow slits spaced 
meters apart. However, by placing a piece of crystal in one of the slits, you are able to make it so that the rays of light that travel through the two slits are Ï out of phase with each other (that is to say, Ao,- ). If you observe that on a screen placed 4 meters from the two slits that the distance between the bright spot closest to center of the pattern is 1.5 cm, what is the wavelength of the laser?
Answer:
The wavelength is 
Explanation:
From the question we are told that
The distance of slit separation is 
The distance of the screen is 
The distance between the bright spot closest to the center of the interference is 
Generally the width of the central maximum fringe produced is mathematically represented as
=> 
=> 
=>
Answer:
y = 52.44 10⁻⁶ m
Explanation:
It is Rayleigh's principle that two points are resolved if the maximum of the diffraction pattern of one matches the minimum the diffraction pattern of the other
Based on this principle we must find the angle of the first minimum of the diffraction expression
a sin θ= m λ
The first minimum occurs for m = 1
sin θ = λ / a
Now let's use trigonometry the object is a distance L = 0.205 m
tan θ = y / L
Since the angles are very small, let's approximate
tan θ = sin θ/cos θ = sin θ
sin θ = y / L
We substitute in the diffraction equation
y / L = λ / a
y = λ L / a
Let's calculate
y = 550 10⁻⁹ 0.205 / 2.15 10⁻³
y = 52.44 10⁻⁶ m
