1) Young's double-slit experiment is carried out by using green, red and blue light, one colour at a time. The fringe widths recorded are $\beta_{G},\beta_{R}$ and $\beta_{B}$ respectively, then A) $\beta_{G}$ > $\beta_{B}$ > $ \beta_{R}$ B) $\beta_{B}$> $\beta_{G}$ > $ \beta_{R}$ C) $ \beta_{R}$ > $\beta_{B}$ > $\beta_{G}$ D) $ \beta_{R}$ > $\beta_{G}$ >$\beta_{B}$ Answer: Option DExplanation:Fringe width $\beta= \frac{\lambda D}{d}$ or $\beta \propto \lambda$ Now, $\lambda_{R} > \lambda_{G} > \lambda_{B}$ $\therefore$ $ \beta_{R}$ > $\beta_{G}$> $\beta_{B}$
