Question

A student holds a laser that emits light of wavelength 641.5 nm. The laser beam passes though a pair of slits separated by 0.400 mm, in a glass plate attached to the front of the laser. The beam then falls perpendicularly on a screen, creating an interference pattern on it. The student begins to walk directly toward the screen at 3.00 m/s. The central maximum on the screen is stationary. Find the speed of the 50th-order maxima on the screen.

Answer 1

A particle at the Large Hadron collider in CERN is moving at 0.99 c as it emerges from a collision event.
A) If these particles live 2.0 microseconds on average when they are at rest, how long would you expect this particle to last in the reference frame of the physicist measuring the particle?