MCQ
Two wavelengths $\lambda_1$ and $\lambda_2$ are used in Young's double slit experiment $\lambda_1=450 \mathrm{~nm}$ and $\lambda_2=650 \mathrm{~nm}$. The minimum order of fringe produced by $\lambda_2$ which overlaps with the fringe produced by $\lambda_1$ is $n$. The value of $n$ is_________.
  • A
    $5$
  • B
    $8$
  • $9$
  • D
    $10$

Answer

Correct option: C.
$9$
c
$\mathrm{n}_2 \lambda_2=\mathrm{n}_1 \lambda_1$

$\frac{\mathrm{n}_2}{\mathrm{n}_1}=\frac{\lambda_1}{\lambda_2}=\frac{450}{650}=\frac{9}{13}$

$\mathrm{n}_2=9$

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