A single slit of width 0.40mm is illuminated by monochromatic light of wavelength 550nm. A screen is placed 1.8m from the slit.
(a) Calculate the linear distance on the screen between the centre of the central maximum and the position of the first secondary maximum.
(b) Using the standard intensity formula for a single-slit pattern, determine the intensity of this first secondary maximum as a percentage of the central maximum intensity.
(c) Comment briefly on the visibility of this secondary maximum to the naked eye in an actual laboratory observation.