Answer:
Explanation:
fringe separation or fringe width is directly proportional to wavelength .
Δ₁ / Δ₂ = wave length of first laser / wavelength of second laser
Δ₁ is fringe separation in first case and Δ₂ is fringe separation in second case.
putting the given values
632.8 / wavelength of second laser = 4.5 / 4.64
wavelength of second laser = 632.8 x (4.64 / 4.5)
= 652.48 nm
652 nm