Hello,

The problem is based on YSDE

The double-slit experiment is a proof in contemporary physics that light and matter may exhibit properties of both conventionally defined waves and particles, as well as the essentially probabilistic nature of quantum mechanical processes.

Angular fringe width, θ/beta= d/λ

Therefore λ=θd

Given d=0.01mm=10^−5m,θ=1 degree = 180/π radians

λ= 180/π×10^−5

=1.74×10^−7 m=0.174×10^−6m=0.174μm

hope you got it

Thank you