Answer:
λ≅

λ≅497 nm
Step-by-step explanation:
In order to find the wavelength of the light from the second source we are going follow the following procedure.
Formula:
Nλ=d*x/l
Where:
N is the order of maximum
λ is the wavelength
d is the distance from central maximum
x/l is the ratio
For first monochromatic source:
We will find the ratio x/l.
=Nλ/d


For second monochromatic source:
Nλ=d*x/l
λ=

λ=

λ≅

λ≅497 nm