In a Young's double experiment , the slits are 1.5 mm apart. When the slits are illuminated by a nonochromatic light source and the screen is kept 1 m apart from the slits ,width of 10 fringes is measured as 3.93 mm . Calculated the wavelength of light used. What will be the width of 10 fringes when the distance between the slits and the screen is increased by 0.5 m . The source of light used remains the same.