In a Young's double slit experiment, two slits are located \( 1.5 \, \text{mm} \) apart. The distance of screen from slits is \( 2 \, \text{m} \) and the wavelength of the source is \( 400 \, \text{nm} \). If the \( 20 \) maxima of the double slit pattern are contained within the central maximum of the single slit diffraction pattern, then the width of each slit is \( x \times 10^{-3} \) \( \text{cm} \), where x-value is _______.
