Answer:
a = 4.8 10⁻⁵ m
Explanation:
The diffraction phenomenon is described by the expression
a sin θ = m λ
How the pattern is observed on a distant screen
tan θ = y / L = sin θ / cos θ
Since the angle is very small in these experiments ’we can approximate the tangent function
tan θ = sin θ = y / L
We substitute
a y / L = m λ
The first minimum occurs for m = 1
a = λ L / y
a = 680 10⁻⁹ 5.5 / 0.078
a = 4.8 10⁻⁵ m
