In Young's double slit experiment, ten slits separated by a distance of 1 mm are illuminated by a monochromatic light source of wavelength 5 x 10^–7 m. If the distance between slit and screen is 2 metre, then separation of bright lines in the interference pattern will be

1.0 mm

$\beta = \frac{\lambda D}{d} = \frac{5\times 10^{-7}\times 2}{10^{-3}} = 1mm$