Question

In the Young's double slit experiment two light beams of wavelengths $\lambda =6000A^o$ and $\lambda =4800A^o$ are used. The distance between two slits is $2.5mm$. The distance between slits and the screen is $1.5m$. The distance of seventh dark fringes for ${\lambda }_2$ from central maximum will be

• A. $1.652mm$
• B. $1.872mm$
• C. $2.872mm$
• D. $2.652mm$

Answer 1

Answer: (B)

$1.872mm$

$y=(n+\frac{1}{2})\frac{\lambda D}{d}$
$y=6.5\left(\frac{4800A^o\times 1.5mm}{2.5mm}\right)$
$y=1.872mm$
option $B$ is correct