MCQ
In Young's double slit experiment using sodium light ( $\lambda$$= 5898 Å$), $92$ fringes are seen. If given colour ($\lambda = 5461 Å$) is used, how many fringes will be seen
- A$62$
- B$67$
- C$85$
- ✓$99$
✓
Answer
Correct option: D.
$99$
d
(d)$({n_1}{\lambda _1} = {n_2}{\lambda _2})$ $\frac{{{n_1}}}{{{n_2}}} = \frac{{{\lambda _2}}}{{{\lambda _1}}} \Rightarrow \frac{{{n_1}}}{{92}} = \frac{{5898}}{{5461}} \Rightarrow {n_1} = 99$
(d)$({n_1}{\lambda _1} = {n_2}{\lambda _2})$ $\frac{{{n_1}}}{{{n_2}}} = \frac{{{\lambda _2}}}{{{\lambda _1}}} \Rightarrow \frac{{{n_1}}}{{92}} = \frac{{5898}}{{5461}} \Rightarrow {n_1} = 99$
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