Savchenko Problem 1.1.4

Physics · mechanics · electromagnetism

Problem

Counters A and B, which register the moment of the arrival of a γ\gamma-quantum, are located at a distance of 2 m from each other. At a point between them a π\pi meson decayed into two γ\gamma-quanta. Find the position of this point if counter 0 A detected the γ\gamma-quantum 10−9 s later than counter B. The speed of light is 3⋅\cdot108 m/s.
Intuitive explanation

The key is recognizing that light travels at a finite speed, so the time difference between detections reveals which counter is closer to the decay point. Since counter A detected its photon later, it must be farther away—the photon had to travel a greater distance. Use the time delay and the speed of light to set up equations for the distances from each counter to the decay point, then solve for the position along the line between them.

Intuitive explanation

The key is recognizing that light travels at a finite speed, so the time difference between detections reveals which counter is closer to the decay point. Since counter A detected its photon later, it must be farther away—the photon had to travel a greater distance. Use the time delay and the speed of light to set up equations for the distances from each counter to the decay point, then solve for the position along the line between them.

Browse the problem library