Question

PLEASE show all of your work thoroughly! thank you!

1. To facilitate traffic flow, many stoplights now have a sensing system based on inductance to determine if a car is waiting at a red light. If that is the case, the light is then switched to green. Using the Internet, write a paragraph explaining how the system works.

Answer 1

This kind of trafiic control system uses an Inductor that is placed under the road in a groove that is a covered. These inductive loops work by detecting the change in inductance. For this first we have to know a little about how electromagnets work, because Inductor is basically an electromagent. Initlally when the switch is turned on in a circuit with a resistor and inductor parallelly connected to battery, bulb glows brightest at first and then starts dimming out as the inductor builds field in it. The speed at which bulb dims out is proprtional to the inductance of the inductor loop. And the inductance of the loop depends on material around the loop. So when a car is parked on the road above the inductor the inductance is increased because car is made of metal. Detecting the changes in inductance tell us wether a car is parked or moving.