Answer:
Explanation:
The wave of light is being reflected two times while going from lower to higher refractive index mediums
So there will be phase reversal two times .
Condition of destructive index
2 μ t = ( 2m+1) λ / 2
Substituting the values
2 x 1.25 x t = ( 2 x 3 + 1 ) x 600nm / 2
2.5 t = 2100 nm
t = 840 nm .
