Question

1. The card reader at your bank’s cash machine scans the information that is coded in a

magnetic pattern on the back of your card. Why must you remove the card quickly rather

than hold it motionless in the card reader’s slot?

(a): to maximize the magnetic force on the card.

(b): to maximize the magnetic force on the mobile charges in the card reader

(c): to generate an electric force on the card.

(d): to generate an electric force on the mobile charges in the card reader.

2. Describe the Physics behind how many traffic lights change when a car rolls up to the

intersection. Explain with figure as well

Answer 1

answer is

(d): to generate an electric force on the mobile charges in the card reader.

when you swipe the card your card will create a changing magnetic field it will causes an induced emf current or electric force on the mobile charges (faraday's law)with respect to magnetic pattern of your card.this induced emf convert in to digital code of voltage and gives to digital cash machine CPU..