a) Why can a laser disc that is written with a blue laser store more information than a laser disc that is written with a red laser?
b)Laser light with a circular cross-section passes through a slit in an opaque card.The slit is shaped as shown below.After passing through the slit and traveling a great distance the beam no longer will have a circular cross section.Which of the spot patterns shown is the most likely shape of the beam after passing through the slit and traveling a great distance.Briefly explain.
