(a) Describe Huygen's Principle. (b) A monochromatic light passes through a narrow slit and forms a diffraction pattern on a screen behind the slit. As the wavelength of the light decreases, describe what happens to the diffraction pattern. (c) A monochromatic light passes through a narrow slit and forms a diffraction pattern on a screen behind the slit. As the slit width increases, describe what happens to the diffraction pattern. (d) Light of wavelength 728.0 nm is incident on a narrow slit. The diffraction pattern is viewed on a screen 88.5 cm from the slit. The distance on the screen between the third order minimum and the central maximum is 1.75 cm. What is the width a of the slit in micrometers (m)