Summary questions 1 a) Sketch an arrangement that may be used to observe the fringe
pattern when light from a narrow slit illuminated by a sodium vapour
lamp is passed through a double slit.
b) Describe the fringe pattern you would expect to observe in a.​

Answer is in the photo. I couldn't attach it here, but uploaded it to a file hosting. link below! Good Luck!

cutt.ly/XzW3SUN

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me