In a Young's interference experimental arrangement incident yellow light is composed of two wavelength 5890 Å and 5895 Å. between the slits is 1 mm and the screen is placed 1 m away. Order upto which fringes can be seen on the screen will be

589

$nλ_2=(n+\frac{1}{2})λ_1$ or $\frac{(n+\frac{1}{2})}{n}=\frac{λ_2}{λ_1}$

or $\frac{1}{2n}=\frac{λ_2-λ_1}{λ_1}=\frac{5895-5890}{5890}=\frac{5}{5890}$

$∴n=\frac{5890}{10}=589$