PHYS 102 Lecture Notes - Lecture 24: Montreal Metro, Electric Generator

• School: McGill University
• Department: Physics
• Course: PHYS 102
• Professor: Nikolaos Provatas

Document Summary

Changing flux bc of rotating conducting loop in magnetic field. In cycle, flux increases then decreases through one loop face. It then repeats the process for the other face of the loop. Current goes in one direction for cycle then in the other direction for the second of the cycle. Loop terminates in two rings that touch leads with reverse polarity every cycle. The montreal metro uses a third rail for electricity, but it could just as easily electrify the tracks themselves. This would mean that the tracks would be connected to a 750v power supply. A metal bar of resistance 1ohm can slide along the metro tracks with negligible friction. A railway engineer attempts to do this calculation using f=ilb with the dimensionally sensible formula i=qv/l for the current, where q is the charge of the electrons making up the current (1. 602e-19c) and v their velocity.