In young's double slit experiment performed using a monochromatic...

Since& the intensity at the central maxima remains unchanged, the change in the path difference& should be an integral multiple of the wavelength. Therefore,

$\Deltax = \left(\mu - 1\right)t = n\lambda⇒ \left(1 . 5 - 1\right)x\lambda = n\lambda⇒ x = \dfrac{n}{0 . 5} = 2n$

For~$n = 1$

$x = 2$