In YDSE, the angular width of a fringe formed an a distant screen is $1^0$ . The wavelength of light used is $6000A^0$ . The spacing between the slits is

Angular fringe width $\theta =1^0=\frac{\pi }{180}rad$

Wavelength $\lambda =6000A^0=6000\times {10}^{-10}m$

Slit distance $d=?$

                      $d=\frac{\lambda }{\theta }$

                        $=\frac{6\times {10}^{-7}}{1^0}$

                       $=\frac{6\times {10}^{-7}}{0.0175}$

                       $=0.0344\times {10}^{-3}m$

               $\therefore d=0.0344mm$