Homework Help is Here – Start Your Trial Now!
Science
Physics
20.6 Electric Hazards and the Human Body There are two known hazards of electricity-thermal and shock. A thermal hazard is one where excessive electric power causes undesired thermal effects, such as starting a fire in the wall of a house. A shock hazard occurs when electric current passes through a person. Shocks range in severity from painful, but otherwise harmless, to heart-stopping lethality. This section considers these hazards and the various factors affecting them in a quantitative manner. Electrical Safety: Systems and Devices will consider systems and devices for preventing electrical hazards. Thermal Hazards Electric power causes undesired heating effects whenever electric energy is converted to themal energy at a rate faster than it can be safely dissipated. A classic example of this is the short circuit, a low-resistance path between terminals of a voltage source. An example of a short circuit is shown in Figure 20.21. Insulation on wires leading to an appliance has wom through, 788 Chapter 20 | Electric Current, Resistance, and Ohm's Law allowing the two wires to come into contact Such an undesired contact with a high voltage is called a short. Since the resistance of the short, r. is very small, the power dissipated in the short, P = v2/r.is very large. For example, if V is 120 V and r is 0.100 2. then the power is 144 kW, much greater than that used by a typical household appliance. Thermal energy delivered at this rate will very quickly raise the temperature of surrounding materials, melting or perhaps igniting them. (a) Figure 20.21 A short circuit is an undesired low-resistance path across a voltage source. (a) Worn insulation on the wires of a toaster allow them to come into contact with a low resistance r. Since P = V/r. thermal power is created so rapidly that the cord melts or burns. (b) A schematic of the short circuit.

20.6 Electric Hazards and the Human Body There are two known hazards of electricity-thermal and shock. A thermal hazard is one where excessive electric power causes undesired thermal effects, such as starting a fire in the wall of a house. A shock hazard occurs when electric current passes through a person. Shocks range in severity from painful, but otherwise harmless, to heart-stopping lethality. This section considers these hazards and the various factors affecting them in a quantitative manner. Electrical Safety: Systems and Devices will consider systems and devices for preventing electrical hazards. Thermal Hazards Electric power causes undesired heating effects whenever electric energy is converted to themal energy at a rate faster than it can be safely dissipated. A classic example of this is the short circuit, a low-resistance path between terminals of a voltage source. An example of a short circuit is shown in Figure 20.21. Insulation on wires leading to an appliance has wom through, 788 Chapter 20 | Electric Current, Resistance, and Ohm's Law allowing the two wires to come into contact Such an undesired contact with a high voltage is called a short. Since the resistance of the short, r. is very small, the power dissipated in the short, P = v2/r.is very large. For example, if V is 120 V and r is 0.100 2. then the power is 144 kW, much greater than that used by a typical household appliance. Thermal energy delivered at this rate will very quickly raise the temperature of surrounding materials, melting or perhaps igniting them. (a) Figure 20.21 A short circuit is an undesired low-resistance path across a voltage source. (a) Worn insulation on the wires of a toaster allow them to come into contact with a low resistance r. Since P = V/r. thermal power is created so rapidly that the cord melts or burns. (b) A schematic of the short circuit.

College Physics
College Physics
11th Edition
ISBN:9781305952300
Author:Raymond A. Serway, Chris Vuille
Publisher:Raymond A. Serway, Chris Vuille
Chapter1: Units, Trigonometry. And Vectors
Section: Chapter Questions
Problem 1CQ: Estimate the order of magnitude of the length, in meters, of each of the following; (a) a mouse, (b)...
See similar textbooks
icon
Related questions
Question

Electric Hazards and the Human Body
• Define thermal hazard, shock hazard, and short circuit.
• Explain what effects various levels of current have on the human body.

20.6 Electric Hazards and the Human Body There are two known hazards of electricity-thermal and shock. A thermal hazard is one where excessive electric power causes undesired thermal effects, such as starting a fire in the wall of a house. A shock hazard occurs when electric current passes through a person. Shocks range in severity from painful, but otherwise harmless, to heart-stopping lethality. This section considers these hazards and the various factors affecting them in a quantitative manner. Electrical Safety: Systems and Devices will consider systems and devices for preventing electrical hazards. Thermal Hazards Electric power causes undesired heating effects whenever electric energy is converted to themal energy at a rate faster than it can be safely dissipated. A classic example of this is the short circuit, a low-resistance path between terminals of a voltage source. An example of a short circuit is shown in Figure 20.21. Insulation on wires leading to an appliance has wom through, 788 Chapter 20 | Electric Current, Resistance, and Ohm's Law allowing the two wires to come into contact Such an undesired contact with a high voltage is called a short. Since the resistance of the short, r. is very small, the power dissipated in the short, P = v2/r.is very large. For example, if V is 120 V and r is 0.100 2. then the power is 144 kW, much greater than that used by a typical household appliance. Thermal energy delivered at this rate will very quickly raise the temperature of surrounding materials, melting or perhaps igniting them. (a) Figure 20.21 A short circuit is an undesired low-resistance path across a voltage source. (a) Worn insulation on the wires of a toaster allow them to come into contact with a low resistance r. Since P = V/r. thermal power is created so rapidly that the cord melts or burns. (b) A schematic of the short circuit.
Transcribed Image Text:20.6 Electric Hazards and the Human Body There are two known hazards of electricity-thermal and shock. A thermal hazard is one where excessive electric power causes undesired thermal effects, such as starting a fire in the wall of a house. A shock hazard occurs when electric current passes through a person. Shocks range in severity from painful, but otherwise harmless, to heart-stopping lethality. This section considers these hazards and the various factors affecting them in a quantitative manner. Electrical Safety: Systems and Devices will consider systems and devices for preventing electrical hazards. Thermal Hazards Electric power causes undesired heating effects whenever electric energy is converted to themal energy at a rate faster than it can be safely dissipated. A classic example of this is the short circuit, a low-resistance path between terminals of a voltage source. An example of a short circuit is shown in Figure 20.21. Insulation on wires leading to an appliance has wom through, 788 Chapter 20 | Electric Current, Resistance, and Ohm's Law allowing the two wires to come into contact Such an undesired contact with a high voltage is called a short. Since the resistance of the short, r. is very small, the power dissipated in the short, P = v2/r.is very large. For example, if V is 120 V and r is 0.100 2. then the power is 144 kW, much greater than that used by a typical household appliance. Thermal energy delivered at this rate will very quickly raise the temperature of surrounding materials, melting or perhaps igniting them. (a) Figure 20.21 A short circuit is an undesired low-resistance path across a voltage source. (a) Worn insulation on the wires of a toaster allow them to come into contact with a low resistance r. Since P = V/r. thermal power is created so rapidly that the cord melts or burns. (b) A schematic of the short circuit.
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 2 steps

SEE SOLUTIONCheck out a sample Q&A here
Blurred answer
Knowledge Booster
Circuits
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, physics and related others by exploring similar questions and additional content below.
Similar questions
  • SEE MORE QUESTIONS
Recommended textbooks for you
College Physics
College Physics
Physics
ISBN:
9781305952300
Author:
Raymond A. Serway, Chris Vuille
Publisher:
Cengage Learning
University Physics (14th Edition)
University Physics (14th Edition)
Physics
ISBN:
9780133969290
Author:
Hugh D. Young, Roger A. Freedman
Publisher:
PEARSON
Introduction To Quantum Mechanics
Introduction To Quantum Mechanics
Physics
ISBN:
9781107189638
Author:
Griffiths, David J., Schroeter, Darrell F.
Publisher:
Cambridge University Press
Physics for Scientists and Engineers
Physics for Scientists and Engineers
Physics
ISBN:
9781337553278
Author:
Raymond A. Serway, John W. Jewett
Publisher:
Cengage Learning
Lecture- Tutorials for Introductory Astronomy
Lecture- Tutorials for Introductory Astronomy
Physics
ISBN:
9780321820464
Author:
Edward E. Prather, Tim P. Slater, Jeff P. Adams, Gina Brissenden
Publisher:
Addison-Wesley
College Physics: A Strategic Approach (4th Editio…
College Physics: A Strategic Approach (4th Editio…
Physics
ISBN:
9780134609034
Author:
Randall D. Knight (Professor Emeritus), Brian Jones, Stuart Field
Publisher:
PEARSON
SEE MORE TEXTBOOKS