Question

In a Young’s double slit experiment the separation between the slits(d) = 0.5 mm and the wavelength used is $\lambda$ = 800 m. Find the total number of maxima that lies between two lines drawn symmetrically from the point right in the middle of the two slits.

• A. 624
• B. 625
• C. 621
• D. 640

Answer 1

The correct option is B 625

$dsin\theta =n\lambda$

$n=\frac{0.5\times {10}^{-3}\times \frac{1}{2}}{800\times {10}^{-9}}$

$=\frac{2500}{8}=312.5$ $\therefore n_{max}=312$

$\therefore$ Total number of maxima between the two lines
$=2\times 312+1=625$