3.1 INTRODUCTIONJust as coal enable

3.1 INTRODUCTION
Just as coal enabled the industrial revolution, electricity is the unseen fuel of modern
life. The use of electricity results in the production of electric and magnetic fields
(EMF). There are two types of EMF classified according to the frequency range:
ELF fields and VLF fields. ELF fields are defined as those having frequencies up to
3 kHz while VLF fields cover the frequency range 3–30 kHz. Because of the quasistatic nature of the EM fields at these frequencies, electric and magnetic fields act
independently of one another and are measured separately. Electric fields created by
voltage and measured in volts per meter are present whenever an electric appliance
is plugged in. The appliance need not be turned on for electric fields to be detected.
Magnetic fields, induced by alternating current and measured using the derived
quantity magnetic flux density in Tesla or Gauss, are present when the appliance
is turned on. The strength of EMF decreases as we move away from their sources.
EMF exposure is commonly found in and around our homes and offices [1].