Single slit problems:

1) How wide is a single slit that produces its first maximum for coherent 661 nm light at an angle 21.3 degree?

2)

Find the wavelength of light that has its third minimum at an angle of 40.10 when it falls on a single slit of width 2.24 ,um. What is the wavelength of light falling on double slits separated by 2.11 pm if the third-order maximum is at an angle of 55.60? Calculate the wavelength of light that has its third minimum at an angle of 30.0 when falling on double slits separated by 3.38 um. Give your answer in nm