A double-slit arrangement produces interference fringes that are$0.25°$ apart using wavelength $600 \mathrm{nm}$. If the angular separation is increased to $0.3°$ by changing the wavelength of the light used, then the new wavelength must be

A beam of light consisting of two wavelengths, $650 \mathrm{nm}$ and $520 \mathrm{nm}$, is used to obtain interference fringes in a Young’s double-slit experiment. Find the distance of the third bright fringe on the screen from the central maximum for wavelength $650 \mathrm{nm}$.

A beam of light consisting of two wavelengths, $650 \mathrm{nm}$ and $520 \mathrm{nm}$, is used to obtain interference fringes in a Young’s double-slit experiment. What is the least distance from the central maximum where the bright fringes due to both the wavelengths coincide?