How is the spacing between fringes in a double slit experiment affected if: (i) the slits separation is increased, (ii) the colour of light used is…

Spacing between fringes in Young's doubles slit experiment $$\beta=\frac{\lambda D}{d} $$ $\displaystyle 1$) $\displaystyle \beta$ decreases as $\displaystyle d$ increases as $\displaystyle \beta \propto \frac{1}{d}$ $\displaystyle 2$) $\displaystyle \lambda_{\text {blue }}<\lambda_{\text {red }}$ as $\displaystyle \beta \propto \lambda$ ∴ fringe width decreases. $\displaystyle 3$) $\displaystyle \beta^{\prime}=\frac{\beta}{\mu} \quad \therefore \beta$ decreases as $\displaystyle \mu>1[\therefore \mu=1.2]$