Hazards of Electricity: Electrical Shock
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Questions and Answers

What is one of the symptoms of electrical shock?

  • Violent muscle contractions (correct)
  • Temporary numbness
  • Mild headache
  • Slight dizziness

    • What influences the severity of electrical shock?

  • Type of clothing worn by the victim
  • Duration and magnitude of the shock (correct)
  • The victim's height and weight
  • Humidity level in the environment

    • What is the final trauma usually determined by in an electrical shock incident?

  • Most critical path 'shock circuit' (correct)
  • Type of electrical appliances involved
  • Magnitude of the shock
  • Physical condition of the victim

    • Why does a given amount of current flow usually cause less trauma to a person in good physical condition?

    <p>Due to lower resistance in healthy individuals</p> Signup and view all the answers

    What is a common consequence of burns caused by electric current involving vital internal organs?

    <p>Respiratory problems</p> Signup and view all the answers

    What is the formula to approximate the energy produced by current flow through body tissues?

    <p>J = I^2.R.t</p> Signup and view all the answers

    Why are burns caused by electric current almost always third-degree?

    <p>Due to burning from the inside of the body</p> Signup and view all the answers

    What is the effect of higher frequencies on the effects of Joule (I2t) heating?

    <p>The effects become less significant</p> Signup and view all the answers

    What are the possible effects of higher voltages in electrical injuries?

    <p>Increased cellular voltage gradients</p> Signup and view all the answers

    What is the main danger of current passage through the body's central nervous system?

    <p>Fatal damage</p> Signup and view all the answers

    At what voltage may the epidermis be punctured, leading to a dramatic increase in current magnitude?

    <p>V &gt; 400 V</p> Signup and view all the answers

    What is the formula for total current flow when a worker contacts a 120-V circuit due to an internal short-circuit in an electric drill?

    <p>$I = \frac{R}{E} + R_2$</p> Signup and view all the answers

    What is the range at which an average individual can let go from an electrical circuit?

    <p>$6-25$ mA (women), $9-30$ mA (men)</p> Signup and view all the answers

    What is generally more likely to cause ventricular fibrillation?

    <p>Long duration of current through the heart</p> Signup and view all the answers

    Which parameter is directly proportional to the energy delivered to the body by current flow?

    <p>Current duration</p> Signup and view all the answers

    What is the final trauma usually determined by in an electrical shock incident?

    <p>Most critical path 'shock circuit'</p> Signup and view all the answers

    What may be a possible symptom of electrical shock?

    <p>Violent muscle contractions</p> Signup and view all the answers

    Why are burns caused by electric current almost always third-degree?

    <p>Burning from the inside of the body</p> Signup and view all the answers

    What does a given amount of current flow usually cause less trauma to a person in good physical condition?

    <p>Higher resistance to electric current</p> Signup and view all the answers

    What factor influences the severity of electrical shock related to the victim?

    <p>Physical condition and responses</p> Signup and view all the answers

    What is the main danger of current passage through the body's central nervous system?

    <p>Threat to cognitive functions</p> Signup and view all the answers

    What is the formula for approximating the energy produced by current flow through body tissues?

    <p>J = I2.R.t</p> Signup and view all the answers

    What can higher voltages cause in electrical injuries?

    <p>Electrical arcing and intense electroporation</p> Signup and view all the answers

    What is the main danger of current passage through the body's central nervous system?

    <p>Fatal damage to the nervous system</p> Signup and view all the answers

    At what voltage can the epidermis be punctured, leading to a dramatic increase in current magnitude?

    <p>&gt; 400 V</p> Signup and view all the answers

    What is the range at which an individual cannot let go, but can be thrown away from the circuit if extensor muscles are involved?

    <p>6–25 mA (women), 9–30 mA (men)</p> Signup and view all the answers

    What is the formula for total current flow when a worker contacts a 120-V circuit due to an internal short-circuit in an electric drill?

    <p>$I = E / (R_1 + R_2)$</p> Signup and view all the answers

    What is generally more likely to cause ventricular fibrillation?

    <p>Short duration of high current flow through the heart</p> Signup and view all the answers

    What does higher frequency do to the effects of Joule (I2t) heating?

    <p>Decreases the effects of Joule heating</p> Signup and view all the answers

    Why are burns caused by electric current almost always third-degree?

    <p>Resulting from deep tissue damage and necrosis</p> Signup and view all the answers

    What is generally not perceptible at currents below 1 mA?

    <p>Strong involuntary reactions</p> Signup and view all the answers

    Study Notes

    Symptoms and Severity of Electrical Shock

    • Symptoms of electrical shock can include confusion, muscle spasms, and loss of consciousness.
    • Severity of electrical shock is influenced by factors like current intensity, duration of exposure, and skin resistance.
    • Final trauma from an electrical shock incident is typically determined by the path the current takes through the body.

    Impact of Physical Condition and Burns

    • A person in good physical condition typically experiences less trauma from the same amount of current due to better body resistance and health.
    • Burns from electric current affecting vital internal organs can lead to serious complications like internal damage or organ failure.
    • Burns caused by electric current are almost always classified as third-degree due to high thermal energy involved.

    Energy and Current Flow Calculations

    • The energy produced by current flow through body tissues can be approximated using Joule's heating formula: (E = I^2 \cdot R \cdot t).
    • Higher frequencies increase Joule heating effects, leading to greater thermal injuries.
    • Total current flow for a worker contacting a 120-V circuit can be calculated based on the specific resistance in the circuit.

    Voltage Effects and Ventricular Fibrillation

    • Higher voltages in electrical injuries can cause more severe burns, deeper tissue damage, and greater current flow through the body.
    • The main danger of current passage through the body's central nervous system is the potential for disrupting vital functions, including cardiac rhythm.
    • The epidermis can be penetrated at voltages around 1000 V, significantly increasing current magnitude.

    Safety Thresholds and Electrical Circuit Interaction

    • An average individual can typically let go from an electrical circuit at currents below 6 mA.
    • If extensor muscles are involved, individuals may be thrown away from the circuit but cannot let go when exposed to higher currents.
    • Currents below 1 mA are generally imperceptible.

    Factors Contributing to Ventricular Fibrillation

    • Ventricular fibrillation is more likely to occur at currents between 50 mA and 100 mA.
    • The energy delivered to the body by current flow is directly proportional to the square of the current (I²).

    Summary of Effects and Consequences

    • Main dangers due to electrical injury include burns, organ damage, and potential death.
    • Electrical shock can have varying consequences based on voltage, current flow, and the physical condition of the victim.

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    Description

    Learn about the nature of electrical hazards with a focus on electrical shock, including the physical stimulation from current flow through the body, current distribution, critical shock circuit, and symptoms of electrical shock.

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