83
R = resistance between two points
Resistance of any material is affected by the type of material, length of material,
temperature of material, and cross-section area of the material that is perpendicular
to the transmission of the electric charge.
Electric and magnetic fields are present where electricity is generated/transmitted/distributed (Fig. 2.28). These fields are omnipresent in our environment.
Electric fields in a circuit are created by potential difference. Higher the potential
difference, the stronger the electrical field.
Extremely low-frequency magnetic fields are categorized as a “possible human
carcinogen” by the International Agency for Research on Cancer (IARC 2002).
Electromagnetic fields exist ubiquitously in our environment. Electric fields are
generated in the atmosphere due to thunderstorms. All materials (e.g., soil) also
have electric properties, e.g., electrical permittivity and conductivity (Hummel
1998; Rabiu et al. 2017).
The electricity used in day-to-day life generates low-frequency electromagnetic
fields. Higher-frequency radio waves are used in day-to-day life in television, radio,
and mobile phone for transmitting information.
Electromagnetic waves are series of invisible waves traveling at a huge speed.
Frequency of electromagnetic wave is the number of occurrences of cycle per unit
time. Wavelength of these waves is the distance between two adjacent waves. Effects
of EMF vary with different frequencies.
Some electromagnetic waves have the ability to break bonds between molecules.
Such waves and are called “ionizing radiation.” Other waves are called “nonionizing radiation.”
Exposure to external magnetic and electric fields at very low frequencies induces
electric fields as well as currents within the body and stimulates excitable tissues
such as muscle and nerve.
Electric current of higher magnitude will affect muscles making fingers into a
fist. Hand touching live wire will grasp the wire firmly, and victim will not be able
to leave the wire with current. Even after stopping the current, the victim may not
reclaim voluntary control of their muscles for some time. Relatively low electric
currents affect heart functioning making heart flutter instead of beating, thereby
hindering flow of blood to vital body organs. Strong enough electric current can also
lead to death due to cardiac arrest and/or asphyxiation. As electric current through a
material results in a release of energy, normally as heat, so in living organisms it
may result in burning of the tissue and organs (Health and Safety Authority 2019).
Apart from electric safety, waste from electrical and electronic equipment is of
great health concern for environmental and health professionals, which is dealt in
detail in the subsequent chapters.
2.7 Electrical and Electronics
R = resistance between two points
Resistance of any material is affected by the type of material, length of material,
temperature of material, and cross-section area of the material that is perpendicular
to the transmission of the electric charge.
Electric and magnetic fields are present where electricity is generated/transmitted/distributed (Fig. 2.28). These fields are omnipresent in our environment.
Electric fields in a circuit are created by potential difference. Higher the potential
difference, the stronger the electrical field.
Extremely low-frequency magnetic fields are categorized as a “possible human
carcinogen” by the International Agency for Research on Cancer (IARC 2002).
Electromagnetic fields exist ubiquitously in our environment. Electric fields are
generated in the atmosphere due to thunderstorms. All materials (e.g., soil) also
have electric properties, e.g., electrical permittivity and conductivity (Hummel
1998; Rabiu et al. 2017).
The electricity used in day-to-day life generates low-frequency electromagnetic
fields. Higher-frequency radio waves are used in day-to-day life in television, radio,
and mobile phone for transmitting information.
Electromagnetic waves are series of invisible waves traveling at a huge speed.
Frequency of electromagnetic wave is the number of occurrences of cycle per unit
time. Wavelength of these waves is the distance between two adjacent waves. Effects
of EMF vary with different frequencies.
Some electromagnetic waves have the ability to break bonds between molecules.
Such waves and are called “ionizing radiation.” Other waves are called “nonionizing radiation.”
Exposure to external magnetic and electric fields at very low frequencies induces
electric fields as well as currents within the body and stimulates excitable tissues
such as muscle and nerve.
Electric current of higher magnitude will affect muscles making fingers into a
fist. Hand touching live wire will grasp the wire firmly, and victim will not be able
to leave the wire with current. Even after stopping the current, the victim may not
reclaim voluntary control of their muscles for some time. Relatively low electric
currents affect heart functioning making heart flutter instead of beating, thereby
hindering flow of blood to vital body organs. Strong enough electric current can also
lead to death due to cardiac arrest and/or asphyxiation. As electric current through a
material results in a release of energy, normally as heat, so in living organisms it
may result in burning of the tissue and organs (Health and Safety Authority 2019).
Apart from electric safety, waste from electrical and electronic equipment is of
great health concern for environmental and health professionals, which is dealt in
detail in the subsequent chapters.
2.7 Electrical and Electronics