First candidate enters the room. The Prof: "What is faster, the sound or the light?"
Student #1: "The light." The Prof: "Nice, and why?" The Student: "When I turn on the radio, first the light and then the sound comes." The Prof: "Out!!!"
The second candidate. Same question. Answer: "The sound." The Prof: "Why that?!?" Student #2: "When I turn on my TV, the sound comes first and then the vision." "OUT!!!"
The professor wonders if the students are too stupid or if he makes the questions too complicated. The third candidate. The Prof: "You are standing on a hill, facing a cannon fired at you, what do you perceive first, the muzzle flash or the bang?"
The Student: "The muzzle flash." The Prof exults and asks, "Can you explain that?" The student hums and haws and then says: "Well, the eyes are ahead of the ears ..."