The phenomenon of generating current/e.m.f. in a circuit by changing magnetic field linked with the circuit is called electromagnetic induction (EMI). In our daily lives, we use (EMI) in many ways without even realiaing it.
Read the above passage and answer the following question :
(i) What is the most universal application of EMI ?
(ii) How is the phenomenon being used to enhance the safety of all our important establishments ?

Explanation

(i) The most universal application of the phenomenon of EMI is in the generation of electricity all over the world. Electricity is the eighth wonder of modern civilized world. It is just impossible to imagine the world without electricity as nothing works without electric power. And this electric power generation is based on hte phenomenon of electromagnetic induction. We are using electricity every moment without realizing the phenomenon of EMI, used in its production.
(ii) All key estabishments like airports, railway stations, bus terminals, shopping malls, defence, scientific research areas etc. are provided with metal detectors at their main entrance. The visitors are to pass through the are of the detector and they are subjected to a series of magnetic field pulses. If the visitor has some metal object like knife, dagger, pistol etc. on his person, the currents induced in these objects create their own magnetic field echo, which is detected. The safety inspectors on duty can then check the visitor more thoroughly.