. In a Youngs double slit experiment 15 fringes are observed on a small portion
of the screen when light of wavelength 500 nm is used.
Ten fringes are observed on the same section of the screen when another light source of wavelength lambda is used.
Then the value of lambda is (in nm ).
The length of silt
x=nβ where n is number of fringes and β is the fringe width
The value of γ is750nm.